Overhaul Service Manual
Contents
1. 10825 46 1 Fastener 47 2 Fastener Screw 48 2 OiPipePugsSS 1 Brg Cap Gasket 1 sSosot8 49 4 Brg Cap Screws 50 1 Rudder kit 7 4 Rudder Bolt 1 32 1 56 7 1 57 1 Cotter Pin Grease Fitting Cap M 4 o 2 3 N e gt 9 02 N i 568 o Noz Housing Capscrew Allen head 1 Noz Housing Capscrew Allen head RIF 5 a a ja 6 2 3 59 Bowl Drain Plug 12JC amp 12JG Package Transom Housing Mounting Kits BM 6491 BM 6492 Transom Housing 99 to 189 Standard gg 1129 5 Uso EN UEM rd 2 Transom Housing Screw 1 4 x 2 Long FH Transom Housing Washer 1 4 Flat 5 23061 1997 poH eA TN 4 WmnsomHowigNet M Hu 2 eet 8 Pines fice PEE E T 2 RubberGasketforTansomHousing 5146 1 Bowi Seal Ring nemi um TI e ET o A ME ie FIT 77 MEC nS REDE 9 Tiller Set Screw 5 16 18 x 3 4 Lg Sq Hd Set Screw Somes q Tut 70 Reverse Cable Adjusting Nut 8592 11 Retaining Clip 65922. SDERKELEY SERVICE MANUAL BERKELEY JET DRIVES INDEX Introduction to jet drives A About jet drives Specific to Berkeley Jet Drives Principles of operation Dynamometer theory Schematic EB Impeller to engine matching 1 Impeller curves 2 Basic engine curves 3 Match per operator requirement 4 Variations for modified engines Trouble Shooting Check List A Excess RPM s 1 Debris in jet 2 Something in impeller 3 Wear ring clearance 4 Worn or dinged impeller High horsepower and big loads 6 Airingestion 7 Loss of speed Loss of engine RPM s 1 2 3 4 5 Fuel Engine tune Overheat Bad thrust bearing Something wrapped in shaft Loss of boat speed constant RPM s 1 2 3 4 5 Added operating weight Reverse gate drag Bottom spray drag Warped boat bottoms Dirty boat bottom Unusual noises Me Clatter or knocking sound 2 Grinding or rubbing sound 3 Squealing or high pitched rotating noise 4 Hammering or thudding sensation Water leaks 1 Packing gland 2 Suction piece gaskets 3 Transom adapter seal a Bowl to adapter b Adapter to transom 4 Inspection cap extension 5 Cooling water hose 6 Cable thru hull attachments Overhaul of Jet Drives A moo m Steering and reversing mechanism Impeller and wear ring Bowl bowl bearing Suction piece packing gland Shaft and bearing assembly INTRODDUCTION TO
3. Note Remove the suction piece assembly pump assembly by removing the bolts and lock wash 5 amp 6 page 28 which secures the suction piece to the intake housing which is fastened to the hull Pry up on the suction piece to break the gasket seal between the suction piece and the intake housing Slide the suction piece aft out the access hole in your boat transom The splined shaft will slip out of the U joint which is fastened to the engine 4 point engine mounts require no support for the engine If you have a 3 point mount which rests on the suction piece housing a suitable lift must be provided for the rear of the engine so the bell housing can be unclamped from the suction piece It is advisable to installa wooden block between the hull and the engine bell housing to safely support the engine while the jet drive is removed Remove the bearing cap capscrew 49 4 each from the bearing housing and tap the bear ing housing to remove it from the suction piece Remove the shaft and bearing assembly from the suction piece using a protective wood block or soft mallet and drive the shaft forward using a heavy hammer Remove the Tru Arc snap ring 31 from the shaft 20 Note Note Press the bearing from the shaft using a press or suitable mechanical bearing removal installation tool Support the bearing on the inner race while pulling it from the shaft if you plan to reuse it Inspect the shaft especially the bowl
4. Note Check reverse gate and steering operation after re assembly to insure full port to star board steering and a full open reverse gate in the forward control position B BOWL AND BOWL BEARING Other than introduction of fresh oil through the oil reserve plugs 48 removal of the bowl is only required if you suspect foreign objects in the bowl vanes loose bowl bearings or you must remove the impeller T Remove the transom housing 1 by disconnecting the reverse gate cable steering cable and transom housing retaining bolts The housing is sealed using gasket 3 6 and O ring 7 Most builders also are liberaf with Silicone Sealant so use of a large screwdriver a wide stiff putty knife or rolling head pry bar may be necessary to break the transom housing loose from the boat transom and jet drive bowl If cable lengths permit the housing may be slid aft and off the bowi If the lengths do not per mit the cable seals must be loosened so the cables can be removed from the transom housing 2 Remove the bowl by removing the 8 bowl to suction piece capscrews 3 4 with a 3 4 box end wrench a Separate bowl from suction piece and slide aft off the impeller shaft b Inspect bowl for damage to the bowl vanes debris in the vanes worn bowl bearings 26 or bad seal 28 Bowl Bearing Replacement a Remove the end cap 11 with 15 16 box end wrench b Drive the bearings forward into the bowl using a bearing rem
5. 42 from lower steering pivot shaft Push shaft up into nozzle area Be cautious the pin does not fall into the bowl and cause loss of time fishing it out It is stainless steel so a magnet does not work Remove the tiller shaft set screw 5 16 3 4 43 using 5 16 open end wrench Note this set screw has a nylon lock button The screws should always be replaced when it has been removed Remove upper woodruff key 3 36 after removing tiller arm and push or tap the tiller shaft 15 down through the nozzle housing Inspect the nylon bushing 29 and discard if worn Inspect the woodruff keys 2 ea in the tiller shaft and the keyways in the nozzle 6 and steering housing 5 If the key way is worn your steering will be loose and steer ing failure is very possible Replace either or both of items 5 amp 6 if they are worn Inspect the O ring 20 on the steering nozzle and replace if damaged A bad O ring causes thrust loss around the nozzle especially in turns and excess water spray 4 Use 12 box end wrench or socket and ratchet to remove the 8 5 16 x 3 4 capscrews 51 which secure the nozzle housing to the after bowl face Remove the nozzle housing and set aside the gasket 17 for replacement 5 Assembly is reversal of steps a through j Make sure all parts are serviceable all threads are clean Use light grease such as Lubriplate on all moving parts to assure easy assembly and free movement 17
6. The impeller has a cast in groove on the hub Use a puller with three or four inside jaws to grip thehub indent Tighten the jacking screw and give ita blow with a ball peen hammer It may be necessary to repeat this procedure several times before the impeller breaks lose Liberal use of a penetrating oil may be required The impeller fits on a straight shaft section with a long keyway There is a shoulder on the shaft which the front of the impeller hub rests against when the impeller is fully seated Inspect the impeller for broken blades cracks or excess wear on the wear ring seal area and dinged or chipped leading edges on the impeller blades a The wear ring area may be dressed if there are groves worn in it and a new wear ring sized to fit the smaller diameter b Small nicks and dings or sand worn impeller blade leading edges may be renewed using a small die grinder hand files and crocus cloth The proper blade shape is similar to an airfoil with the flat side on the top of the blade and the curved shape on the underneath side of the blade when you look atthe impeller from the front The edge should not be knife sharp but finished to about a 1 32nd radius Try to keep the leading edges of the blades all the same length Remove the wear ring amp insulator 13 amp 14 from the suction piece by prying the parts out This is facilited with a small rolling head pry bar You will remove the wear ring and the plastic liner a Discard
7. 13 Nyliner Bearing BM 6592 4 8 14 Reverse Cable Packer Nut 6593 546 1 1 15 Reverse Cable Packer Washer BM 6593 1 1 Sti 2 2 16 Reverse Cable Packer Grommet BM 6593 1 1 11 sows 1 r Steering Tube Nut 7 8 5 13530 18 Steering Tube Bushing EI ON Steering Adapter Tube Morse Steering Onl msasa h Steering Adapter Tube Rideguide amp Teleflex p2s48985 Steering Adapter Tube Steermaster amp Marmac 20 Adapter Steermaster Steering Only 5965 1 21 Capscrew Str to Tiler Morse amp Ridegude 594 31 22 Spacer Nut Str to Tiler Morse 8 Ridegude 2657 1 3 24 Drain Plug B 07572 Enos i 237 26 12J Parts 6491 6492 12JC amp 12JG PACKAGE TRANSOM HOUSING MOUNTING KITS Transom Housing Gaskets Tiller Steering Adapter Tube and all necessary fasteners For 0 to 90 Transom Catalog Number 0203 B 06492 For 9 to 18 Transom Catalog Number 0203 B 06491 __ _ od OOD 9 27 12J Package Intake Adapter Mounting Kits BM 5812 BM 6309 BM 6667 INTAKE ADAPTER MOUNTING KITS Includes Intake Adapter Grate Gasket and all necessary fasteners Flat Inside Mount with Fins and Flat Head Machine Screws 1 Catalog Number 0203 B 06309 12 degree with fins and Flat Head Machine Screw
8. T T ciem is u3MOd3iSuOH LIVHS REVOLUTIONS PER MINUTE HUNDREDS 3 STANDARD SIZES A2 THRU E OF IMPELLERS DIMENSIONS INCHES IMPELLER SMALL SIZE DIA SMALL DIAMETER 9 i L a MACH GLE 2 AN Figure 1 24 Wrench Rod End Packing Rings Hand Hold Cover 1 Suction Piece Seal Bowl Bearings Brg Cap Seal Bowl Seal Nyliner Bearings Ring 12JG Parts BM 7338 Per Unit Description sym Description Seating 2 X p Ring 1 Suction Piece s 2 Hand Hole Cover Grease Fitting 35 1 Nozzle Woodruff 1 Packing Gland q pH 8 BeaingCap 1315338 38 2 Packing Gland Bolt 9 1 ReverseBucket 10451 39 2 Packing Gland Nut 10 1 Pumpsnat 0556 40 11 5 GLockWasher SC t 1 soso 41 Bow Bolts 12 1 Shatt Sleeve 1 51499 42 3 Nozzle amp Rev Bucket Capscrew Wear Ring 310125 4s 1 14 1 50068 44 1 Barbed Cgnnector 15 1 TillerShat s15396 45 2 5 6 Hand Hole Nuts
9. bearing end and straitness in the spline through bear ing fit areas Repair or replace as indicated Undersized bowl bearings are not available as factory replacement parts so the shaft must be sized to original specifications Use the undamaged forward area to obtain shaft diameter measurements Suction piece packing rings are removed easily once the shaft is removed Remove packing gland nuts 39 and remove the split packing gland Pry out old packing rings 23 set of 5 and slip new packing rings into place Remove the packing rings in a similar manner if the shaft is in place Use a packing puller or make one with a long self tapping sheet metal screw The packing rings are split for installa tion over the shaft Make sure to stagger the splits in the rings in 90 degree intervals Reinstall the shaft and bearing assembly in the suction piece after installing the bearing on the shaft Install bearing so the thrust side no groove for bearing balls or side marked for inner race thrust is toward the shoulder on the impeller shaft The thrust goes from the shaft shoulder to the inner bearing race and through the bearing bells to the front face of the outer race The bearing housing 8 absorbs the impeller th ust and clamps the outer race so it cannot spin or move fore and aft Slide the shaft and bearing into the suction piece and slide the bearing home by pressing or driving on the outer race only Driving on the shaft will dama
10. in full throttle RPM is an indication of pump wear water flow blockage or air ingestion The rule is simple RPMs up look for wear rocks in grate ski rope in jet etc RPMs down check thrust tail shaft and universal joints for proper operation and look to the engine fuel spark com pression etc F Impeller to Engine Matching The following curve shows the horsepower absorption characteristics for a Berkeley 12 size jet drive 1 Berkeley Impeller Chart 2 Engine to Berkeley Jet Drive Impeller Match See page 24 In factory installed installations the impeller selected will provide the best average performance and is designed to keep the maximum engine RPM s possible well within safe operating limits You can obtain small increases in performance or tune the jet drive to your type or style of boating by making an impeller trim change If your engine is locked at 4200 RPM let s say and it will make power through 4800 RPM then a smaller trim size for increased RPM should result in a higher top speed providing the power gain was sufficient In this situation you will need more RPMs at water ski and cruising speeds You however may not care much about absolute top end and be much more interested in economy quiet engines strong low to mid range accelaration and the best water ski and cruise conditions You would want to use a larger trim impeller and limit your top end RPM s This set up will provide the most miles per
11. longer ride as free as it originally did 11 Restore speed by Losing weight Fix the trailer Straighten the boat bottom Adjust the reverse gate shift cable linkage Loss of Engine RPM s Again remembering the dynamometer theory loss of RPM is either due to loss of engine power or internal friction in the jet drive or drive shaft 1 Poor fuel water in fuel old fuel engine fuel system problems plugged filters on fuel tank suction tube check fuel flow Engine out of tune a Check tuning dwell plugs compression etc b Has the throttle linkage slipped so W O T is no longer possible Engine is overheating a Check for free water tlow through the block A garden hose on the inlet water line will let you see if you have water flow b Is there water flow from the pump into the cooling hose Leaves or gravel can get into the supply line Clean it out 6 Did the flow valve if you have one vibrate itself into the off or low flow position Adjust it for proper flow then use a tie wrap to fix it so it cannot open or close d Blown head gaskets or exhaust riser manifold gaskets can let high pressure gases into the engine cooling system Check for water in the oil water fouled spark plugs Bad Thrust Bearing If the thrust bearing is failing or locking up the friction will pull the engine down Check if the bearing housing is hotter than usual It should be cool or warm to the touch Listen for rotating n
12. or outboard Because the Berkeley has more maneuvering ease than other drive systems you should learn to handle your craft quickly and become an expert around the docks in a short time See Page 23 for diagram A jet handles quite differently than the traditional prop and rudder What makes a jet different makes it better It doesn t depend upon hull movement to attain full power A prop unloads as for ward speedis attained which lets the engine rev to full power that is only available at full boat speed With a jet you hit the throttle and take off right now with full power When you reverse a jet drive you reverse right now with full power When you turn the jet plus the rudder swing you around in a super tight circle You can move a jet boat sideways into tight docking situations by switching from forward to reverse while coordinating the steering You will note onething with the Berkeley Jet Drive which is totally differentthan other drive systems If your Berkeley Jet Drive is not equipped with the standard some models optional rudder there will be no steering force exerted under a no throttle or engine off condition This is not unsafe Without underwater appendages your jet drive propelled boat will immediately return to a straight line and coast to a stop if the power is cut quickly Use of a rudder is recommended if you want to have more control even under power off or low thrust conditions You will learn to keep a lit
13. the wear ring and insulator if worn b Install a new wear ring and insulator in standard or an undersized fit according to the impeller eye size of your impeller The wear ring should have rotating clearance only when the impeller is installed Check final fit by splipping the impeller into the installed wear ring and rotating the impeller d Re check fit after the bowl is installed 19 Reinstall the impeller reverse order Note Use brown Loctite or Neverseize on the shaft and key then slide the impeller onto the shaft with the key started into the keyway Use a tube type driver which fits over the impeller hub and seat the impeller tight against the shaft shoulder Install the impeller nut and tighten it to about 75 foot pounds or until the impeller is seated against the shaft shoulder If you drive the impeller onto the shaft with excess force and the front of the shaft is not supported your hammer blows will be transferred to the thrust bearing and small flats will be made on the ball bearing along with dents in the bearing races Result prema ture thrust bearing failure The impeller should be a hand to light press fit on the shaft Shaft and bearing assembly repairs or replacement are possible once you have removed the impeller and the suction piece is out of the boat or the engine has been removed Removal of the entire jet drive or suction piece assembly only are preferable to pulling the engine a
14. weight dramaticlly of any of your passengers or purchased a new 68 quart cooler The speed of your jet boat is primarily a function of power to weight ratio if you added weight especially towards the bow you will use speed a little or a lot depend ing on how much weight and how it effects your crafts Longitudinal Center of Gravity LCG Check your reverse gate and make sure it does not drag in the jet stream Any drag is an application of reverse thrust and down goes your speed Adjust your cable linkage check for loose connectors bent control pivot arms loose bushings in the reverse gate pivot pins Bottom spray drag can also slow you down Perhaps water is hitting the reverse chute since you raised your cavitation plate or you installed a drop nozzle and now the whole steering section drags at speed 13 A common cause of lost speed is the development of a hook in the running surface Over a period of time trailers may sag support bunkers break or one is knocked out of adjustment and the hull takes a new shape If you get a hook in the last eight feet of run ning surface there will be a tendency for the hull to run flatter move glued down and the extra bottom drag slows you down The remedy is simple but involves lots of work expense or both depending on how bad who does the work and how exact you want the bottom blueprinted Taking out a hook or straightening crooked running surfaces requires grinding off some of the hig
15. JET DRIVES A About Jet Drives The Jet Drive is Simple A jet drive is a water pump which is driven by a automotive engine that has been specially prepared for marine use The engine is mounted within the hull and connected direc tly to the pump There is no clutch or gear box The jet receives water through an intake grate in the bottom of the boat and ejects the flow beyond the transom and through a steerable nozzle The pump impeller in ejecting the water creates an equal force in the opposite direction which propels the boat forward Steering is done by swinging the nozzle and rudder right or left as desired The boat s attitude can be controlled by pointing the nozzle up or down within a controlled range models with underway trim Reverse is accomplished by lowering a reverse gate across the outflow diverting the jet stream for ward beneath the hull Lowering the reverse gate when the boat is going forward can stop the boat virtually within its own length Stopping should be done carefully to prevent passengers or free objects from being tossed forward There is no extra strain on the engine or the Jet Drive when going from forward to reverse The drive system can t detect the change its rotation and load are not affected The jet drive does not know how heavy your boat is or what speed the boat runs Simply the Berkeley jet drive in your boat is matched to the engine and will deliver about 1400 1800 pounds of thrust whi
16. ack to the engine crankshaft If you experience such a sensation shut down or go to idle RPM s immediately and determine the cause Come home at slow speed if you cannot inspect the impeller or intake area while on the water Removal of the foreign object is ususally all you will need to do There is usually no mechanical damage unless the condition is extreme or you persist in high RPM operation E WATER LEAKS There are only a few areas for water leaks on the jet drive and installation b 2 Leakage at the packing gland A very slow drip at idle is not bad if the packing gland is too tight you can burn it so it will not seal If the leak is excessive or you suspect an air leak under hard acceleration tighten the packing gland just enough to eliminate the excess leak more than 10 20 drops per minute at idle If you cannot tighten the packing gland to eliminate the leak or you need excess bolt torque the packing must be replaced Don t panic it can be done without a jet drive tear down or pulling the engine See the overhaul section of this manual 15 2 Leaks at the Suction Piece Gasket This can usually be eliminitated by re torquing the bolts If you have to replace the gas ket the jet drive will have to be removed from the boat See the overhaul section 3 Transom Adapter Seal a The transom adapter is sealed to the boat with a gasket Apply a new bead of silicon around the joint as a first step repair o
17. e area to see if something is hung in the grate You will have to go overboard so first try this sometimes just shutting off the engine and restarting it will do the trick especially if there are large weeds or a plastic bag sucked up against the grill If the slippage is still there and the grill is clear you probably have 2 Something in the impeller To inspect the impeller you will need to remove the hand hole cover Use caution Your jet may be below static water line Remove the cover and you risk flooding the boat If this is the case beach the boat so it cannot sink or limp back to the trailer Invest in an extension for your inspection hand hole if it can be fitted Owners of transom mount E amp F models OK Your hand hole is outside the boat It may be difficult to get to but there is no danger of flooding the boat Once the hand hole is open feel all around the impeller for a small stick piece of plastic rock between the impeller blades or even ski ropes or long weeds wrapped around the impeller shaft Remove any debris you find reinstall the cover and try to accelerate If you are still slipping you probably have something lodged way back in the impeller blades Take another look Also check the impeller blades to see if there is a piece missing This is very unlikely but an ingested rock can break a blade Wear Ring Clearance The wear ring acts as a seal between the high pressure water in t
18. gallon a quieter boat less engine wear and tear and will be more comparable to atypical stern drive setup At 35 MPH the difference between an impeller at 3200 RPM 125 SHP and a impeller at 4900 RPM 140 SHP is easily seen and felt These same two impellers would probably end up being 4200 RPM 280 SHP and 5200 RPM 820 SHP on the top end You should apply these rules a Load the engines for best low and mid range performance b Unload the engines for higher top end RPM and speed provided you have adequate horsepower gain 4 Impeller matching variations for high performance engines Engine modification falls into two categories Changes which require higher RPM s in order to reflect a power gain A few of these changes higher lift larger duration camshafts higher compression more or bigger carburetors These mod ifications will provide more power but are usually accomplished by increased RPM s and a torque curve which is moved 500 to 1000 RPM or more up the scale If the impeller is too big you may be disappointed and discover you have worked hard and spent lots of cash to end up with little or no RPM gain or even lost RPM s As a rule of thumb you should always decrease your impeller trim one size i e to when going to a hotter cam The jet drive needs lots of torque on the top end and very little below 3000 RPM so you must carefully match your new torque curve HP curve to the im
19. ge the thrust bearing resulting in premature bearing failure Tighten the packing gland lightly just unt there is slight drag on the impeller shaft Final adjustment should be made with the shaft turning and the pump shaft submerged Refer to step C item 5 for impeller reinstallation Reinstall the suction piece with shafi bearing and impeller wear ring in the boat using a new gasket 3 page 28 Installation of the suction piece assembly rather than the entire jet drive makes positioning the unit and shaft insertion into the splined U joint easier You may prefer to fully assemble the jet drive before installation In this case help from a second person or suspending the drive from the overhead may expedite getting the shaft splines into the U joint and the suction piece aligned without gasket damage 21 Note You may find it helpful to use heavy grease or a gasket compound to help hold the gasket in place on the intake housing Reinstall all components in the reverse order to their disassembly making sure all seals bet ween the boat and the jet drive are intact so there will be no leaks when you water test your boat Include all parts lists Special Notes All models of Berkeley jet drives are similiar so only minor variation in assembly disassem bly are required Be especially careful of the rubber accordion boots used underwater on some models A small puncture or tear will result in a flooded boat Berkeley E
20. ght you can do everything except replace the thrust bearing without taking the entire jet drive out of the boat Only in rare instances should engine removal ever be necessary A Disassembly re assembly of the steering and reversing mechanism 16 In this assembly all the parts external and no seal between the jet drive and hull needs to be broken unless you are replacing cable packing glands items 18 15 and 16 See the tran som housing parts illustration 27 Normally repairs in this area will center around replacement of gasket 17 and the 4 bushing 29 page 7 on the lower pivot shaft open steering shaft and the two reverse gate shafts ile a Remove the pins 55 15 and 16 2 ea in order to separate the reverse gate from the steering nozzle and the steering nozzle and the steering nozzle 6 from the nozzle housing 5 Remove the 5 16 X 1 socket head cup screw 42 from the left and right reverse gate pivot shafts Push the pivot shafts into the steering nozzle until the reverse gate is free Use of a sol vent such as liquid wrench WD 40 and a drift and hammer may be required where units have been in service a long time especially in salt or brackish water Lift off the reverse gate inspect and set aside for replacement repaint or re installation Remove 2 nylon bushing 29 and inspect Either replace or save if no wear or damage is apparent Remove 5 16 1 socket head capscrew
21. h spots if possible filling in the hollows and making a new straight surface for about the last eight feet of the boat bottom If you determine the trailer needs repair or adjustment as well do it now or your newly straightened boat bottom will soon be crooked again A dirty boat bottom has resulted in speed loss or even the inability to get upon plane on many a boat Boats left in the water grow weeds and algae and can loose as much as 10 MPH in only one week A 200 mile tow on dusty roads heavily traveled interstate or through a rain storm can leave enough road film on the running surface to scrub off an easy 5 MPH in a free running 70 MPH water craft UNUSUAL NOISES If you are aware of the sounds normally heard when your boat is running changes in sound will not only indicate potential problems but help you diagnose the problem Here are a few typical sounds 7 Clatter Knocking Sound a Check the U joint very carefully The needle bearing may be failing need lube or the shaft splines may be dry b Make sure the bolts tying the U joint to the flywheel are tight Loose bolts allow the U joint flange to work and can allow the flywheel to spin loose from the crankshaft Check the tail shaft bearing by reaching in through the inspection hand hole and feeling for up and down or side to side motion There should be no discernible shaft movement Grinding or Rubbing Sound If you see no visible cause for the grinding or r
22. he impeller bowl area and the low or no pressure water in the suction piece if the wear ring is loose there will be excess back flow of high pressure water and you will experience the following symptoms Any or all of a Loss of a few MPH on the top end b Require more RPM s to maintain same cruise or ski speed c Onhard acceleration you will get several hundred RPM s overrun then the engine will load back down to normal or slightly higher RPM s The only cure for a worn wear ring is disassembly ofthe bowl and impeller and replacement of the wear ring Sometimes the impeller skirt seal area will be worn excessively as well Worn or Dinged Impeller Operations in sandy rocky or dirty water will cause the leading edge of the impeller blades to be dinged off After awhile the edge is no longer almost sharp but rounded off or even chipped or dented The symptoms of a worn impeller are the same as for a worn wear ring Diagnosis is simple Feel the impeller blades through the hand hole or look at them through the grill with a flashlight to enable you to see the impeller If the edge is rounded bumpy chipped or has other damage the impeller must be removed and either replaced or the edge rounded to its original contours Generally an impeller overhaul and fitting of a new wear ring is all you will requireto restore as before performance to your jet drive High Horsepower and Big Loads Occasionally you will load up al
23. l your gear and crew in order to make one run to the campsite oracross the lake If you hit the throttle hard at low speed you may overpower the impeller and cause it to cavitate Usually you can accelerate easily and get up on plane without over rewing If you cannot either reduce your load or operate at suitably reduced throttle In the event you have a worn impeller or wear ring sudden high RPM s at off plane boat speeds will induce cavitation much faster than when your jet drive is like new Operator Suggestions Air Ingestion There are several types of air ingestion a Thefirstairingestion is caused by the impeller packing being worn loose This air inges tion will be under high throttle acceleration The suction of the impeller causes air to flow into the suction piece between the impeller shaft and packing A typical symptom of air ingestion of this type is high RPM s on acceleration which drop once the boat is at speed Usually worn packing will be indicated by leaking at the packing gland both at rest and at speed Replace the packing or tighten the packing gland 10 b Certain boats will induce air ingestion at speed by funneling air down the edge of the keel a strake or past a thru hull fitting Air ingestion of this type is usually indicated by proper acceleration and load RPM s than an increase in RPM s with either loss of speed or no speed increase Sometimes a slight turn will make the tendency worse or
24. le pumping 3000 to 4000 gallons of water every minute at a pressure of 60 to 180 pounds per square inch PSI B Berkeley Jet Drive Specifics The Berkeley jet drive is a mixed flow design part axial flow part centrifugal with a 12 size designation this 12 size designation is from water well sizing meaning the bowl will 12 well casing The original technology for Berkeiey comes from the hydraulic principals used in the design of single through multi stage line shaft turbine pumps which are used for submerged application in all types of water well or fluid transfer systems The balance of centrifugal and axial flow pump characteristics assures you of adequate thrust velocity for good performance in the popular boat speed ranges from 30 to over 60 MPH The efficiency of the jet drive is readily seen once speeds in the 40 plus miles per hour ranges are reached Minor changes in the nominal 37 4 diameter nozzle are possible and may be effective in fine tuning Usually a slightly larger diameter for boats with top speeds below 45 MPH and a small decrease in nozzle diameter where speeds above 65 MPH are possible C Principals of Operation jet drive should have been installed your boat with a correct impeller to match the engine sup plied with the jet drive There is no requirement to change this impeller in an effort to increase out of the hole thrust or obtain better top speed Your jet drive is easy to maintain The
25. oises such as squeaking grinding or a rough vibration Note A failed thrust bearing can lock up and you will twist the impeller shaft or it will let the impeller shaft ride forward and the impeller will eat itself up on the wear ring and suction piece 12 The forward thrust can force the crankshaft forward and put excess strain on the main bearing thrust bearing If you suspect a bad thrust bearing come home easy and save some big bills for parts other than a new bearing Something Wrapped the Shaft If you pick up lots of fishing line a floating rope or your ski rope it can wrap up and fill the suction piece cavity or get between the wear ring and impeller Remove the item through the hand hole opening using a sharp knife hack saw blade etc to cut the mess loose Sometimes it is necessary to pull the bowl and impeller LOSS OF BOAT SPEED Constant RPM s When you experience a reduction in boat speed yet your full throttle RPM s are the same as before it is safe to initially assume there is nothing wrong with the jet drive at least as far as it s internal condition is concerned Once again please remember the Dynamometer theory The jet drive is absorbing the same power at the same RPM s so itis putting out the same amount of thrust Before you head off for a jet drive overhaul take a look at these areas Have you added extra fuel tank started carrying two new sets of water skis changed
26. or insert model jet drives do not have an intake housing The suction piece is bonded to the hull Removal of the shaft and bearing assembly requires removal of the engine We would like to thank Jack Seastrom for his help with this manual His knowledge and expertise were invaluable 22 Handles Differently A jet handles quite differently than the traditional prop and rudder What makes a jet different makes it better It doesn t depend upon hull movement to attain full power A prop unloads as forward speed is obtained which lets the engine rev to full power that is only available at full boat speed With a jet you hit the throttle and take off right now 23 with full power When you reverse a jet drive you reverse right now When you turn the jet plus the rudder swing you around in a super tight circle You can move a jet boat sideways into tight docking situations by switching from forward to reverse while coordinating the steering 203 10 10 83 SUPERSEDES Curve 203 Sec 3 Pg 2 02 e ua o lt gt Z O 4 CURVE DATE BERKELEY PUMP COMPANY MODEL 12J JET DRIVE HP RPM CURVE POWER DEMAND OF JET DRIVE MODEL 12J ae ri wm HENE BE T
27. oval tool or any suitable drift which passes the bowl end cap threads and has a shoulder to seat on the bowl bearing Drive first bearing 26 into bore from the front side until the bearing face is flush withe bore shoulder d Drive rear bearing 3 26 into bowl from the back side until bearing face is flush with bore shoulder e Install bowl bearing end 11 using Loctite brown Install lip seal in bowl counter bore with the lip facing forward This seal does not keep oil in it keeps debris and high pressure water out of the bowl bearing T Note Worn bowl vanes may be renewed by filling the dings and bluntedges off until there is a fine edge facing the water The bowl vanes should be dressed so all the edges are the same distance from the front of the bowl 18 Note Impeller and Wear Ring Remove the impeller nut 32 using a 1 13 16 box end wrench ora 1 13 16 socket which has been modified so it will slip over the impeller shaft and has a holding handle welded on The impeller nut is a right hand thread and turns counter clockwise for removal In cases where the impeller nut is frozen to the shaft due to extensive immersion in salty or chemically tainted water it may be necessary to use a penetrating oil apply heat or even use atorch to cutthe nut Since the impeller shaft is stainless steel careful application of a cutting _ torch will not damage the shaft or shaft threads Use caution Note
28. peller SHP absorption curve If you also add cubic inches then an impeller size change may not be needed Engine modifications which are basically adding horsepower at the same i e a blower turbos nitrous system will either do well with the same impeller as stock and turn a few hundred more RPM s or will benefit from a larger trim impeller are examples You turn 4600 stock and are at the peak of your stock horsepower curve Addition of a nitrous kit might give you an additional 100 HP Using the same impeller you will either gain 500 RPM and be off the cam curve or you can switch to a larger trim impeller to absorb the additional SHP at about the same RPM as before The alternative solution is to leave the impeller the same change the cam and valve train to be more effective at higher RPM s and get a gross power gain which is the sum of the nitrous added power and effect of the stronger cam ll TROUBLE SHOOTING CHECK LIST A Excess RPM s Using the jet drive as a dynamometer excess RPM s must indicate one thing Something is preventing the jet drive from absorbing the power available according to the Impeller Horsepower Absorption Chart Here are the most common problems 1 Debris in the jet The boat takes a lot of RPM s to get or stay on plane or may not get on plane at all There may be accompanying vibrations or water thudding noises as well Cure Shut down the engine Remove the ignition key Probe the intak
29. performance may actually increase if the air stream is deflected away from the intake The remedy is to remove the air trap or modify the water flow down the boat bottom so this air is deflected towards the chines and away from the intake 6 At speed some boats become so loose and free running there is no hull in the water to make a smooth water flow high pressure path for water to follow into the suction piece The flatter the bottom less dead rise the sooner this problem will develop The symptoms are rapid and frequent momentary jumps in RPM s as the impeller grabs air unloads then grabs water and reloads Aside from accelerated wear on the thrust bearing and impeller the condition contributes to excess RPM s and blown engines If you operate on choppy or rough water at high speeds and experience this type of cavitation you can either slow down keep a very quick throttle foot or hand install a RPM limiter set 200 to 400 RPM s above your normal RPM s or plan on bent pushrods floated valves and broken connecting rods 7 Loss of Speed See items 1 2 3 4 5 If none of these account for the speed loss then look at these items a Reverse gate has slipped down and is dragging in the jet stream b You added weight to the boat Speed is a power to weight relationship so every extra pound of fuel gear or whatever costs a bit of speed The bottom of your boat has changed due to trailer sag broken bunkers etc and the boat will no
30. r replace the gasket b The seal between the bowl and transom adaptor is either silicon O ring or both You can re seal this area with more silicone sealer or pull the transom adaptor and replace the O ring 4 Inspection Cap Extension Water leakage and air induction are prevented by an O ring Keep the O ring clean free of sand and lightly lubricated If the O ring is cut hardened or no longer an effective seal replace it Do not over tighten the cap bolts You can warp the cap and it will not seal Make sure the cap wrench is in place so the retainer bolts cannot work loose and allow the cap to be pushed out by water pressure 5 Cooling Water Hose and Cable Thru Hull Seals These areas and connections should be kept snug to prevent water leakage Replace the water hose cable seals expansion boots every 3rd year as insurance against failure and a possible flooded boat OVERHAUL OF JET DRIVE Itis essential you are familiar with section an Il of this manual Proper trouble shooting will help you determine which parts must be removed from your jet drive or the boat in order to perform the necessary repairs or parts replacement Starting at the back of the jet outside the boat all the parts for steering reversing and trim control are accessible Next you have the bowl and impeller assembly and wear ring and finally the suction piece shaft and thrust bearing assembly and front packing gland assembly With careful thou
31. re are few parts in a jet drive The direct drive shaft has a thrust and tail bearing The impeller is fixed to the shaft and completely enclosed The intake grate screens out most trash but if tough weeds string or a small rope pass the grate and remain in the impeller these are easily removed through a hand hole which is normally covered With no gears and so few parts overhaul of a jet drive may not be necessary for several years or hundreds of hours of use Parts are largely interchangeable and readily available Access is simple and there s a minimum of downtime The engine is heavy duty automotive type expertly modified for marine use Maintenance is much the same as you would expect with a car Berkeley Jet Drives compare favorably with other types of propulsion on fuel consumption Any engine uses excessive gas when pushed toward maximum RPM At skiing speed a large V 8 can compare very favorable on fuel costs for a day of cruising skiing and picnicking Using the 12J as an example With RPM reduced to 7096 of maximum fuel needed is reduced to only 32 of maximum while speed is maintained at 6696 of maximum Thus at two thirds full speed fuel use is cut to less than one third resulting in twice as many miles traveled per gallon Since jets use ordinary automotive grade gasoline without expensive mixing with oil by seldom exceeding 50 MPH you can have a day s fun for little if any greater cost than running a smaller
32. s 2 Catalog Number 0203 B 05812 Flat Outside Mount with fins and Flat Head Machine Screws 5 Catalog Number 0203 B 06667 Required Per Unit Description Part No BM 5812 BM 6309 BM 6667 Int Adapt 12 with Fins Wl cue ME ont ilii RC Int Adapt Flat Bottom with Fins wp Uu lee Int Adapt Flat Outside Mt w Fins La DEC The 3 tr Rock Grate Seetoe f 2B __ Weedless Grate 2 a Sa Required 1 1 Gasket Suction to Intake Adapter 1 1 1 Grate to Intake Adapter Fasteners 4 1 4 20 x 3 4 Lg Philips Taptite Screws S 26402 4 Jet Drive to Intake Adapter Fasteners 5 5 16 18 x 1 Lg Hex Hd Machine Screw 5 23540 d 14 14 14 6 5 16 Lock Washer S 23088 14 14 Hull to Intake Adapter Fasteners r 7 A 1 4 20NC x 2 Lg F H Machine Screw 5 25672 14 16 7 5 16 20NC x 2 Lg Machine Screw S 25682 8 A 1 4 20NC x 2 1 2 Lg Machine Screw S 25674 2 po m 1 4 20NC Hex Nuts S 23481 16 1 29 9 B 5 16 18 Hex Nuts S 15981 E 10 A 1 4 Flat Washers 5 23061 16 18 10 8 5 16 Flat Washers S 23062 28
33. tle throttle on when slowing from high speed so you always have a power steering thrust force available D The Dynamometer Theory Your Berkeley Jet Drive operates in the same way a fluid dynamometer is used to measure engine output Because the imlpeller horsepower curves supplied by Berkeley are very accurate this curve will tell you the engine power being absorbed at any RPM Youcan look atthe B impeller curve for example and see it requires 150 shaft horsepower SHP to turn 3800 revolution per minute RPM If you ski at 35 MPH and the engine must turn 3800 RPM then you are using 150 SHP to drive your boat The Berkeley Jet Drive also measures absolute maximum SHP available from each impeller by absorbing all the power available at some RPM As an example you have a Berkeley Jet Drive with high performance engine If the impeller is an A trim and you can get 4700 RPM then you are pro ducing and absorbing 320 SHP Trouble shooting using the dynamometer theory is very simple if you keep two principles in mind 1 impeller can never absorb more horepower than shown on the impeller curve If you experience loss of RPM s your problem is either mechanical i e seizing jet drive bearings or is in the engine 2 impeller absorbs less horsepower only when there is water flow interruption wear or other causes which are not mechanical Since the engine will not start making more power of its own accord any increase
34. ubbing sound and all the shaft bearings appear to have the correct clearances it is a good precaution to pull the bowl and impeller If a rock or other abrasive object is between the impeller and the wear ring or other parts of the jet drive assembly it can cause excess wear and cut the impeller apart cut a groove in the bowl or suction piece or destroy the wear ring 14 Squealing or High Pitched Rotating Noise This type of sound almost always comes just before total failure of the thrust bearing Another cause can be an object between the impeller and a non rotating element of the jet drive A If you detect this sound check the bearing housing It will get hot if you are about to loose a thrust bearing Come home slowly if you must Remember a failed thrust bearing can lock the shaft let the shaft and impeller assembly spin in an uncontrolled arc All of these items will do further mechanical damage and necessitate additional repair expense Hammering or Thudding Sensation The water hammer or pounding sensation is usually caused by an object which is lodged in the blades of the impeller or between the bowl vanes Another cause is intermittent water flow disruption A trailing bow rope that has an end whipping just inside the suction piece would be a good example A water hammer if severe enough for a long enough period of time can break the impeller cause the bowl to crack or break open and may transfer uneven rotating stress b
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