Specifications - Discount Marine
Contents
1. 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 ENGINE R P M 70808 15 Initial Timing 1 BTDC 90 861329 1 MARCH 1999 Page 4B 15 IGNITION SYSTEM TOTAL SPARK ADVANCE Page 4B 16 30 20 15 10 5 500 SERVICE MANUAL NUMBER 26 MAX MIN 1000 1500 2000 2500 3000 3500 4000 4500 5000 ENGINE R P M 70808 15 Initial Timing 1 ATDC 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM 35 30 25 20 15 TOTAL SPARK ADVANCE 10 5 212 m ELE 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 ENGINE R P M 70808 15 Initial Timing 2 ATDC 90 861329 1 MARCH 1999 Page 4B 172. 4 Replace and tighten distributor hold down bolt and clamp Connect primary lead to coil Also install spark plug and coil secondary wires if removed IMPORTANT Wires must be installed in supports to prevent cross firing Firing order is 1 3 4 2 5 Install rotor 6 Time ignition as outlined under Ignition Timing in this section 7 Replace distributor cap Page 4B 8 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM Engine Disturbed 1 8 9 Locate No 1 piston in firing position by either of two methods described below a Remove No 1 spark plug and with finger on plug hole crank engine until compres sion is felt in No 1 cylinder Continue cranking until pointer lines up with timing mark on crankshaft pulley or b Remove rocker cover and crank engine until No 1 intake valve closes continuing to crank slowly until pointer lines up with timing mark on crankshaft pulley Position distributor to opening in block in normal installed attitude Position rotor to point toward front of engine with distributor housing held in installed attitude then turn rotor counterclockwise approximately 1 8 turn more to the left and push distributor down to engage camshaft It may be necessary to rotate rotor slightly until camshaft engagement is felt While pressing down firmly on distributor housing engage starter a few times to make sure oil pump shaft is engaged Install hold down clamp and bolt and
3. Reading should be infinite If not replace pickup coil 90 861329 1 MARCH 1999 Page 4B 13 IGNITION SYSTEM SERVICE MANUAL NUMBER 26 4 Repeat Step 3 with ohmmeter connected to GREEN lead Reading should be infinite If not replace pickup coil 5 Set ohmmeter to Rx100 scale Connect ohmmeter to GREEN and WHITE pickup coil leads Reading should be constant unchanging value in the range of 500 1500 ohms If not replace pickup coil Be certain to flex leads by hand during this test to locate pos sible intermittent open circuits loss of continuity If any exist replace pickup coil Page 4B 14 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM Advance Curve 35 30 25 20 15 TOTAL SPARK ADVANCE 10 Module Part Number 811637 Module Advance See Notice Initial Timing 1 81001 1 ATDC2 2 ATDC Total Advance 23 1Serial number break 0L340999 and below unless specified differently below 2Serial number break 0K001529 0L097000 Timing changes to 1 ATDC only if engine experiences a cylinder head gasket failure that has blown out toward the intake exhaust manifold on the port side of the engine 3Serial number break 0L341000 and above NOTICE Advance curve includes initial timing DO NOT add initial timing degrees to total advance degrees MAX MIN
4. 12 With timing light still connected start the engine and run at IDLE Verify that timing did advance to e If initial timing is 1 BTDC 12 BTDC plus or minus 2 At 2400 2800 rpm maximum total advance is obtained and should be 23 BTDC plus or minus 2 e If initial timing is 1 14 BTDC plus or minus 2 At 2400 2800 rpm maximum total advance is obtained and should be 25 BTDC plus or minus 2 e If initial timing is 2 15 BTDC plus or minus 2 At 2400 2800 rpm maximum total advance is obtained and should be 26 BTDC plus or minus 2 13 Stop the engine and remove the timing light Component Tests The following tests can be made with the distributor and coil mounted on or off the engine The test procedures will check each component of the distributor and ignition coil Distribu tor cap and rotor should be checked for corrosion cracks carbon tracks or wear Replace if needed Testing Ignition Module In order to test the module an approved module tester such as Kent Moore Tester J24642 or equivalent must be used Be certain to follow the manufacturer s directions precisely for proper results However do not overlook that corrosion on the terminals of the module could cause improper ignition action and should therefor be inspected and cleaned if needed Page 4B 12 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM Testing Ignition Coil 1 If not alr
5. IGNITION SYSTEM SERVICE MANUAL NUMBER 26 Specifications Timing 1Timing must be set using a special procedure as outlined in this section Timing cannot be properly set using the conventional method 2Serial number break 0L096999 and below 3Serial number break 0L097000 0L0340999 4Serial number break 0L341000 and above Spark Plugs Spark Plug Gap 035 In 0 9 mm AC MR43LTS 3 0L NGK BPR6EFS Champion RS12YC GM 4 Cylinder In line Firing 50683 Firing Order 1 3 4 2 Page 4B 4 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM Description EST or Electronic Spark Timing is a High Energy Ignition System HEI The distributor itself has no centrifugal advance mechanism or devices The spark plug wires are a carbon impregnated cord conductor with a silicone rubber jacket It is important they be handled with care and routed so as not to cross each other or to be in contact with other parts of the engine to prevent rubbing The EST System uses a square coil with epoxy covered windings to protect against mois ture and arc over The timing cannot be set the same way that other ignition systems were 70106 a Distributor with Spark Plug Wires b Wires WHITE Used in Timing Procedure c Wire from Shift Interrupt Switch d Distributor Harness e Engine Harness Wire PURPLE AND GRAY f Coil EST uses a magnetic pulse generator and an electronic module to primary circuit current Inte
6. eady done disconnect wiring from ignition coil Connectors are molded and keyed to assure proper positioning The terminal e feeds 12 volts to the distributor NOTE Upon reinstallation first install black connector distributor harness to coil Then install gray connector engine harness 2 Set ohmmeter to Rx100 scale and connect one lead to 12 volt terminal b of coil and the other lead to ground d any clean metal on the coil frame Reading should be infi nite If not replace coil 3 Set ohmmeter to Rx100 scale and connect to 12 volt terminal b and terminal c Reading should be approximately 4 ohms If not replace coil 4 Set ohmmeter to Rx1 scale and connect to 12 volt terminal b and tachometer terminal f Reading should be approximately 4 ohms If not replace coil 5 Set ohmmeter to Rx100 high scale Connect ohmmeter to 12 volt terminal b and to coil high tension post a Reading should be between 7800 and 8800 ohms If it reads outside of this range replace coil Testing Pickup Coil 70105 a Connector b GREEN Lead c WHITE Lead d Distributor Housing Remove distributor cap 2 Identify the two pickup coil leads On almost all applications these two leads are one WHITE and one GREEN Remove the connector that houses these two leads from the module 3 Set ohmmeter to Rx1 scale Connect one lead of ohmmeter to WHITE lead and the other to distributor housing
7. ilver 91 818812A1 or fabricate a jumper wire using a 6 in 150 mm section of 16 gauge wire with two male bullet terminal ends connected 5 Bypass the shift interrupt switch as follows a Disconnect wires at shift interrupt switch b Temporarily join the engine harness wires together IMPORTANT Do not fail to reconnect these two wires to the shift interrupt switch when timing procedures are complete Page 4B 10 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM 6 Aim timing light at timing tab located on the timing gear cover and crankshaft torsional damper Check the timing Refer to Specifications 72328 Typical 7T Adjust timing by loosening distributor clamp and rotating distributor body as required until timing mark on damper or pulley lines up with the mark on tab specified in Specifications Tighten clamp and recheck location of timing mark 8 Aim timing light at timing tab and recheck location of timing mark Repeat Step 7 until timing is correct 9 Stop the engine Torque distributor hold down bolt to 20 Ib ft 27 Nm 10 Reconnect the two wires to the shift interrupt switch 75553 90 861329 1 MARCH 1999 Page 4B 11 IGNITION SYSTEM SERVICE MANUAL NUMBER 26 IMPORTANT Be sure to remove jumper wire before returning engine to service otherwise timing will not advance 11 Remove jumper wire at distributor white leads 70103 a WHITE Leads b Jumper Lead
8. le engine is running Do not reverse battery cable connections System is negative ground Do not disconnect battery cables while engine is running Page 4B 6 90 861329 1 MARCH 1999 SERVICE MANUAL NUMBER 26 IGNITION SYSTEM Cleaning And Inspection Spark Plugs Inspect each plug individually for badly worn electrodes glazed broken or blistered porcelain and replace plug where necessary Inspect each spark plug for manufacturer and heat range All plugs must be the same manufacturer and number or heat range Refer to Specifications for spark plug num bers Check spark plug gaps with a round feeler gauge Adjust if necessary 50674 Spark Plug Detail a Porcelain Insulator b Check For Cracks In This Area of Porcelain c Shell d Proper Gap e Side Electrode Gap Adjustment f Center Electrode File Flat When Adjusting Gap IMPORTANT Tapered seat spark plugs are not interchangeable with non tapered with gasket spark plugs 4 Clean spark plug seating area DO NOT use gaskets on taper seat plugs Install spark plugs and torque to 22 Ib ft 30 Nm Heat transfer and a gas tight seal must be achieved Spark Plug Wires Bom os 5 Inspect spark plug wires for damage Check spark plug wires for continuity Replace any wires that are cracked cut or have damaged spark plug boots Replace any wires that do not show continuity from end to end Reinstall spark plug wires in proper orde
9. r IMPORTANT Proper positioning in spark plug wires is important to prevent cross firing 90 861329 1 MARCH 1999 Page 4B 7 IGNITION SYSTEM SERVICE MANUAL NUMBER 26 Distributor Cap and Rotor 1 Loosen distributor cap retaining screws 2 Remove distributor cap 3 Clean cap with warm soap and water and blow off with compressed air 4 Check cap contact for excessive burning or corrosion Check center contact for deterioration IMPORTANT Distributor caps for marine use should have brass contacts alumi num contacts should not be used 5 Check cap for cracks or carbon tracks using magneto analyzer 6 Remove rotor 7 Check for burned or corroded center contact 8 Check rotor for cracks and carbon tracks using magneto analyzer 9 Install rotor on shaft Be sure rotor is completely seated on shaft 10 Place cap on distributor 11 Tighten retaining screws securely Distributor Installation Engine Not Disturbed Install new gasket on distributor housing 2 Turn rotor approximately 1 8 turn in a counter clockwise direction past mark previously scratched on distributor housing 3 Work distributor down into position in engine block with distributor positioned as noted during removal IMPORTANT It may be necessary to move rotor slightly to start gear into mesh camshaft gear but rotor should line up with mark when distributor is down in place Distributor shaft must enter oil pump shaft for complete installation
10. rnally the Pulse Generator or magnetic pick up assembly takes the place of conven tional points A timer core on the main shaft of the distributor has external teeth which align with an equal number of pole piece teeth four for a four cylinder engine The electronic module is small enough to allow it to be mounted inside the distributor and contains the cir cuits necessary for dwell control and advance of the timing 90 861329 1 MARCH 1999 Page 4B 5 IGNITION SYSTEM SERVICE MANUAL NUMBER 26 Molded into the module is a two prong connector for the coil terminals and four prong con nector Only three of the four terminals of the second connector are used by MerCruiser one for the shift interrupt and two white leads are used to freeze advance for properly setting initial timing Inside the distributor the pick up coil attaches to the module at a molded prong connector QX AO 55 Magnetic Pulse Generator b Electronic Module c Two Prong Connector d Four Prong Connector e Pick up Coil Connector f 9 70107 Pole Piece Teeth External Teeth Precautions When performing the following procedure be sure to observe the following Be sure that engine compartment is well ventilated and that no gasoline vapors are present to avoid the possibility of fire Be sure to keep hands feet and clothing clear of moving parts Do not touch or disconnect any ignition system parts whi
11. snug up bolt Turn distributor body slightly until points just open and tighten distributor clamp bolt Place distributor cap in position and check that rotor lines up with terminal for No 1 spark plug Install cap Install cap distributor primary lead to coil Check and connect spark plug wires if they have been removed Wires must be installed in their proper location in supports to prevent cross firing Firing order is 1 3 4 2 Install rotor Replace distributor cap 10 Time ignition as outlined under Ignition Timing in this section Ignition Timing IMPORTANT Failure to follow the timing procedure instructions will result in improper timing causing performance problems and possible severe engine damage 1 2 Connect timing light 91 99379 or similar to No 1 spark plug wire Connect power sup ply leads on light to 12 volt battery Refer to Specifications Engine Rotation and Firing Order for cylinder numbering and location Connect a shop tachometer to engine NOTE Before starting engine make sure the timing tab and mark on damper are clean Chalk or white paint on timing mark on damper may help visibility 90 861329 1 MARCH 1999 Page 4B 9 IGNITION SYSTEM SERVICE MANUAL NUMBER 26 3 Start engine and run at idle speed until it reaches normal operating temperature 70103 a WHITE Leads b Jumper Lead 4 Install a jumper wire between the two WHITE leads on the distributor Use Quicks
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