IGNITION SYSTEM SERVICE MANUAL NUMBER

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 Specifictions Timing Timing (At Idle rpm) 1 1 BTDC 2 / 1 ATDC 3 / 2 ATDC 4 1 Timing must be set using specil procedure s outlined in this section. Timing cnnot be properly set using the conventionl method. 2 Seril number brek: 0L096999 nd below 3 Seril number brek: 0L097000-0L0340999 4 Seril number brek: 0L341000 nd bove. Sprk Plugs Sprk Plug Gp 3.0L.035 In. (0.9 mm) AC-MR43LTS NGK-BPR6EFS Chmpion RS12YC GM 4-Cylinder In-line Firing 50683 Firing Order 1-3-4-2 Pge 4B-4 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 Description IGNITION SYSTEM EST or Electronic Sprk Timing is High Energy Ignition System (HEI). The distributor itself hs no centrifugl dvnce mechnism or devices. The sprk plug wires re crbon-impregnted cord conductor with silicone rubber jcket. It is importnt they be hndled with cre, nd routed so s not to cross ech other or to be in contct with other prts of the engine to prevent rubbing. The EST System uses squre coil with epoxy covered windings to protect ginst moisture nd rc-over. The timing cnnot be set the sme wy tht other ignition systems were. b c e d - Distributor with Sprk Plug Wires b - Wires (WHITE) Used in Timing Procedure c - Wire from Shift Interrupt Switch d - Distributor Hrness e - Engine Hrness Wire (PURPLE AND GRAY) f - Coil f 70106 EST uses mgnetic pulse genertor nd n electronic module to primry circuit current. Internlly the Pulse Genertor, or mgnetic pick-up ssembly, tkes the plce of conventionl points. A timer core on the min shft of the distributor hs externl teeth which lign with n equl number of pole piece teeth (four for four cylinder engine). The electronic module is smll enough to llow it to be mounted inside the distributor, nd contins the circuits necessry for dwell control nd dvnce of the timing. 90-861329--1 MARCH 1999 Pge 4B-5

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 Molded into the module is two-prong connector for the coil terminls nd four prong connector. Only three of the four terminls of the second connector re used by MerCruiser (one for the shift interrupt nd two white leds re used to freeze dvnce for properly setting initil timing). Inside the distributor, the pick-up coil ttches to the module t molded prong connector. h g e f d - Mgnetic Pulse Genertor b - Electronic Module c - Two Prong Connector d - Four Prong Connector e - Pick-up Coil Connector f - Timer Core g - Pole Piece Teeth h - Externl Teeth b c 70107 Precutions WARNING When performing the following procedure, be sure to observe the following: Be sure tht engine comprtment is well ventilted nd tht no gsoline vpors re present, to void the possibility of fire. Be sure to keep hnds, feet nd clothing cler of moving prts. Do not touch or disconnect ny ignition system prts while engine is running. Do not reverse bttery cble connections. System is negtive ( ) ground. Do not disconnect bttery cbles while engine is running. Pge 4B-6 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 Clening And Inspection Sprk Plugs IGNITION SYSTEM 1. Inspect ech plug individully for bdly worn electrodes, glzed, broken or blistered porcelin nd replce plug where necessry. 2. Inspect ech sprk plug for mnufcturer nd het rnge. All plugs must be the sme mnufcturer nd number or het rnge. Refer to Specifictions for sprk plug numbers. 3. Check sprk plug gps with round feeler guge. Adjust if necessry. e b c f d 50674 Sprk Plug Detil - Porcelin Insultor b - Check For Crcks In This Are of Porcelin c - Shell d - Proper Gp e - Side Electrode (Gp Adjustment) f - Center Electrode (File Flt When Adjusting Gp) Sprk Plug Wires IMPORTANT: Tpered set sprk plugs re not interchngeble with non-tpered (with gsket) sprk plugs. 4. Clen sprk plug seting re. DO NOT use gskets on tper set plugs. Instll sprk plugs nd torque to 22 lb-ft (30 Nm). Het trnsfer nd gs-tight sel must be chieved. 1. Inspect sprk plug wires for dmge. 2. Check sprk plug wires for continuity. 3. Replce ny wires tht re crcked, cut or hve dmged sprk plug boots. 4. Replce ny wires tht do not show continuity from end to end. 5. Reinstll sprk plug wires in proper order. IMPORTANT: Proper positioning in sprk plug wires is importnt to prevent cross firing. 90-861329--1 MARCH 1999 Pge 4B-7

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 Distributor Cp nd Rotor 1. Loosen distributor cp retining screws. 2. Remove distributor cp. 3. Clen cp with wrm sop nd wter nd blow off with compressed ir. 4. Check cp contct for excessive burning or corrosion. Check center contct for deteriortion. IMPORTANT: Distributor cps (for mrine use) should hve brss contcts, luminum contcts should not be used. 5. Check cp for crcks or crbon trcks using mgneto nlyzer. 6. Remove rotor. 7. Check for burned or corroded center contct. 8. Check rotor for crcks nd crbon trcks using mgneto nlyzer. 9. Instll rotor on shft. Be sure rotor is completely seted on shft. 10. Plce cp on distributor. 11. Tighten retining screws securely. Distributor Instlltion Engine Not Disturbed 1. Instll new gsket on distributor housing. 2. Turn rotor pproximtely 1/8 turn in counter-clockwise direction pst mrk previously scrtched on distributor housing. 3. Work distributor down into position in engine block with distributor positioned s noted during removl. IMPORTANT: It my be necessry to move rotor slightly to strt ger into mesh cmshft ger, but rotor should line up with mrk when distributor is down in plce. Distributor shft must enter oil pump shft for complete instlltion. 4. Replce nd tighten distributor hold-down bolt nd clmp. Connect primry led to coil. Also instll sprk plug nd coil secondry wires, if removed. IMPORTANT: Wires must be instlled in supports, to prevent cross-firing. Firing order is 1-3-4-2. 5. Instll rotor. 6. Time ignition s outlined under Ignition Timing, in this section. 7. Replce distributor cp. Pge 4B-8 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 Engine Disturbed IGNITION SYSTEM 1. Locte No. 1 piston in firing position by either of two methods described below.. Remove No. 1 sprk plug nd, with finger on plug hole, crnk engine until compression is felt in No. 1 cylinder. Continue crnking until pointer lines up with timing mrk on crnkshft pulley, or b. Remove rocker cover nd crnk engine until No. 1 intke vlve closes, continuing to crnk slowly until pointer lines up with timing mrk on crnkshft pulley. 2. Position distributor to opening in block in norml instlled ttitude. 3. Position rotor to point towrd front of engine (with distributor housing held in instlled ttitude), then turn rotor counterclockwise pproximtely 1/8-turn more to the left nd push distributor down to engge cmshft. It my be necessry to rotte rotor slightly until cmshft enggement is felt. 4. While pressing down firmly on distributor housing, engge strter few times to mke sure oil pump shft is engged. Instll hold-down clmp nd bolt nd snug up bolt. 5. Turn distributor body slightly until points just open nd tighten distributor clmp bolt. 6. Plce distributor cp in position nd check tht rotor lines up with terminl for No. 1 sprk plug. Instll cp. 7. Instll cp, distributor primry led to coil. Check nd connect sprk plug wires, if they hve been removed. Wires must be instlled in their proper loction in supports to prevent cross-firing. Firing order is 1-3-4-2. 8. Instll rotor. 9. Replce distributor cp. 10. Time ignition s outlined under Ignition Timing, in this section. Ignition Timing IMPORTANT: Filure to follow the timing procedure instructions will result in improper timing cusing performnce problems nd possible severe engine dmge. 1. Connect timing light (91-99379 or similr) to No. 1 sprk plug wire. Connect power supply leds on light to 12 volt bttery. Refer to Specifictions - Engine Rottion nd Firing Order, for cylinder numbering nd loction. 2. Connect shop tchometer to engine. NOTE: Before strting engine mke sure the timing tb nd mrk on dmper re clen. Chlk or white pint on timing mrk on dmper my help visibility. 90-861329--1 MARCH 1999 Pge 4B-9

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 3. Strt engine nd run t idle speed until it reches norml operting temperture. b 70103 - WHITE Leds b - Jumper Led 4. Instll jumper wire between the two WHITE leds on the distributor. Use Quicksilver 91-818812A1, or fbricte jumper wire using 6 in. (150 mm) section of 16 guge wire with two mle bullet terminl ends connected. 5. Bypss the shift interrupt switch, s follows:. Disconnect wires t shift interrupt switch. b. Temporrily join the engine hrness wires together. 75552 75499 IMPORTANT: Do not fil to reconnect these two wires to the shift interrupt switch when timing procedures re complete. Pge 4B-10 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 IGNITION SYSTEM 6. Aim timing light t timing tb, locted on the timing ger cover nd crnkshft torsionl dmper. Check the timing. Refer to Specifictions. 73664 Typicl 72328 7. Adjust timing by loosening distributor clmp nd rotting distributor body s required until timing mrk on dmper or pulley lines up with the mrk on tb specified in Specifictions. Tighten clmp nd recheck loction of timing mrk. 8. Aim timing light t timing tb nd recheck loction of timing mrk. Repet Step 7 until timing is correct. 9. Stop the engine. Torque distributor hold down bolt to 20 lb-ft (27 Nm). 10. Reconnect the two wires to the shift interrupt switch. 75552 75499 75553 90-861329--1 MARCH 1999 Pge 4B-11

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 IMPORTANT: Be sure to remove jumper wire before returning engine to service, otherwise timing will not dvnce. 11. Remove jumper wire t distributor white leds. b 70103 Component Tests Testing Ignition Module - WHITE Leds b - Jumper Led 12. With timing light still connected, strt the engine nd run t IDLE. Verify tht timing did dvnce to : If initil timing is 1 BTDC: 12 BTDC, plus or minus 2. At 2400-2800 rpm mximum (totl) dvnce is obtined nd should be 23 BTDC (plus or minus 2 ). If initil timing is 1 ATDC: 14 BTDC, plus or minus 2. At 2400-2800 rpm mximum (totl) dvnce is obtined nd should be 25 BTDC (plus or minus 2 ). If initil timing is 2 ATDC: 15 BTDC, plus or minus 2. At 2400-2800 rpm mximum (totl) dvnce is obtined nd should be 26 BTDC (plus or minus 2 ). 13. Stop the engine nd remove the timing light. The following tests cn be mde with the distributor nd coil mounted on or off the engine. The test procedures will check ech component of the distributor nd ignition coil. Distributor cp nd rotor should be checked for corrosion, crcks, crbon trcks or wer. Replce if needed. In order to test the module, n pproved module tester, such s Kent-Moore Tester (J24642 or equivlent), must be used. Be certin to follow the mnufcturer s directions precisely for proper results. However, do not overlook tht corrosion on the terminls of the module could cuse improper ignition ction nd should therefor be inspected nd clened if needed. Pge 4B-12 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 Testing Ignition Coil IGNITION SYSTEM 1. If not lredy done, disconnect wiring from ignition coil. Connectors re molded nd keyed to ssure proper positioning. The terminl (e) feeds 12 volts to the distributor. NOTE: Upon reinstlltion, first instll blck connector (distributor hrness) to coil. Then instll gry connector (engine hrness). 2. Set ohmmeter to Rx100 scle nd connect one led to 12 volt terminl (b) of coil nd the other led to ground (d), ny clen metl on the coil frme. Reding should be infinite. If not, replce coil. 3. Set ohmmeter to Rx100 scle nd connect to 12 volt terminl (b) nd terminl (c). Reding should be pproximtely.4 ohms. If not, replce coil. 4. Set ohmmeter to Rx1 scle nd connect to 12 volt terminl (b) nd tchometer terminl (f). Reding should be pproximtely.4 ohms. If not, replce coil. 5. Set ohmmeter to Rx100 high scle. Connect ohmmeter to 12 volt terminl (b) nd to coil high tension post (). Reding should be between 7800 nd 8800 ohms. If it reds outside of this rnge, replce coil. Testing Pickup Coil c d b - Connector b - GREEN Led c - WHITE Led d - Distributor Housing 1. Remove distributor cp. 70105 2. Identify the two pickup coil leds. On lmost ll pplictions these two leds re one WHITE nd one GREEN. Remove the connector tht houses these two leds from the module. 3. Set ohmmeter to Rx1 scle. Connect one led of ohmmeter to WHITE led nd the other to distributor housing. Reding should be infinite. If not, replce pickup coil. 90-861329--1 MARCH 1999 Pge 4B-13

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 4. Repet Step 3 with ohmmeter connected to GREEN led. Reding should be infinite. If not, replce pickup coil. 5. Set ohmmeter to Rx100 scle. Connect ohmmeter to GREEN nd WHITE pickup coil leds. Reding should be constnt, unchnging vlue in the rnge of 500-1500 ohms. If not, replce pickup coil. Be certin to flex leds by hnd during this test to locte possible intermittent open circuits (loss of continuity). If ny exist, replce pickup coil. Pge 4B-14 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 Advnce Curve IGNITION SYSTEM Module Prt Number: 811637 Module Advnce: See Notice Initil Timing: 1 BTDC 1 / 1 ATDC 2 / 2 ATDC 3 Totl Advnce: 23 1 Seril number brek: 0L340999 nd below unless specified differently below 2 Seril number brek: 0K001529-0L097000 Timing chnges to 1 ATDC only if engine experiences cylinder hed gsket filure tht hs blown out towrd the intke exhust mnifold on the port side of the engine. 3 Seril number brek: 0L341000 nd bove. NOTICE Advnce curve includes initil timing. DO NOT dd initil timing degrees to totl dvnce degrees. 35 30 TOTAL SPARK ADVANCE 25 20 15 MAX. MIN. 10 5 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Initil Timing 1 BTDC ENGINE R.P.M. 70808-15 90-861329--1 MARCH 1999 Pge 4B-15

IGNITION SYSTEM SERVICE MANUAL NUMBER 26 35 30 TOTAL SPARK ADVANCE 25 20 15 MAX. MIN. 10 5 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Initil Timing 1 ATDC ENGINE R.P.M. 70808-15 Pge 4B-16 90-861329--1 MARCH 1999

SERVICE MANUAL NUMBER 26 IGNITION SYSTEM 35 TOTAL SPARK ADVANCE 30 25 20 15 MAX. MIN. 10 5 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Initil Timing 2 ATDC ENGINE R.P.M. 70808-15 90-861329--1 MARCH 1999 Pge 4B-17