ELECTRICAL SYSTEMS 4 71855 B IGNITION SYSTEM
Tle of Contents Pge Identifiction............................ 4B - 1 Replcement Prts Wrning.............. 4B - 2 Sprk Plugs.......................... 4B - 2 Sprk Plug Wires..................... 4B - 2 3.0L Breker Point Ignition Prestolite Distriutor System...................... 4B - 3 Torque Specifictions.................... 4B - 3 Tools/Luricnts/Selnts................ 4B - 3 Specifictions........................... 4B - 3 Coil................................. 4B - 3 Distriutor........................... 4B - 3 Sprk Plugs.......................... 4B - 3 Firing Order.......................... 4B - 3 Distriutor Advnce Curves............ 4B - 4 Precutions.......................... 4B - 5 Distriutor Cp nd Rotor.............. 4B - 5 Contct Points....................... 4B - 5 Replcement......................... 4B - 6 Condenser........................... 4B - 7 Coil................................. 4B - 8 Ignition Resistnce Wire............... 4B - 8 Distriutor Repir....................... 4B - 8 Removl............................ 4B - 8 Disssemly......................... 4B - 9 Ressemly......................... 4B - 9 Distriutor Instlltion.................... 4B - 9 Engine Not Distured................. 4B - 9 Engine Distured.................... 4B - 10 Ignition Timing......................... 4B - 10 Pge (DDIS) Digitl Distriutorless Ignition System........................ 4B - 11 Specifictions....................... 4B - 11 Torque Specifictions................ 4B - 11 Tools/Luricnts/Selnts............... 4B - 11 Sprk Plugs......................... 4B - 11 Overspeed Prevention Control........ 4B - 11 Description............................ 4B - 12 DDIS System Components.............. 4B - 12 Sprk Advnce Control................. 4B - 13 Advnce Curve Chrt (Reference Only)... 4B - 13 MCM 3.0 L DDIS Models................ 4B - 13 Sprk Advnce Control................. 4B - 14 Advnce Curve Chrt (Reference Only)... 4B - 14 MCM 3.0 LX (DDIS) Models............. 4B - 14 Components Tests..................... 4B - 15 Ignition Amplifier..................... 4B - 15 Ignition Coil......................... 4B - 16 Motion Sensor...................... 4B - 17 Shift Interrupter Switch............... 4B - 17 Motion Sensor......................... 4B - 18 Removl........................... 4B - 18 Instlltion.......................... 4B - 18 DDIS Ignition Timing.................... 4B - 19 Delco EST Ignition..................... 4B - 20 Torque Specifictions................... 4B - 20 Tools/Luricnts/Selnts............... 4B - 20 Specifictions.......................... 4B - 20 Sprk Plugs......................... 4B - 20 Component Tests...................... 4B - 22 MCM 3.0L, 3.0LX with EST.............. 4B - 23 NOTICE For informtion nd procedures on trouleshooting, refer to SECTION 1C. 4B -- 0 IGNITION - SYSTEM 90-816462 2-695
Identifiction DELCO EST (ELECTRIC SPARK TIMING) 70103 BREAKER POINTS IGNITION 74551 Replcement Prts Wrning! WARNING Electricl, ignition nd fuel system components on your MerCruiser re designed nd mnufctured to comply with U.S. Cost Gurd Rules nd Regultions to minimize risks of fire nd explosion. Use of replcement electricl, ignition or fuel system components, which do not comply with these rules nd regultions, could result in fire or explosion hzrd nd should e voided. 74549 DIGITAL DISTRIBUTORLESS IGNITION SYSTEM (DDIS) 90-816462 2-695 IGNITION SYSTEM - 4B - 1
3.0L Breker Point Ignition Prestolite Distriutor System Torque Specifictions Fstener Loction L. Ft. N m Distriutor Clmp 3/8-16 20 27 Sprk Plugs (14 mm) 15 20 Tools/Luricnts/Selnts Mercury Mrine Specil Tools Description Dwell Meter 91-59339 Mgneto Anlyzer 91-76032 Prt Numer Remote Strter Switch 91-52024A1 Timing Light 91-99379 Volt/Ohm Meter 91-99750 Timing Jumper 91-818812A1 Description Module Tester Kent-Moore Tools J24642 Prt Numer Distriutor Condenser* Model 3.0L.18 -.25 mfd Point Dwell 39-45 Point Gp Point Spring Tension Timing NOTE: * Use Mgneto Anlyzer Sprk Plugs.016 in. (0.5mm) 20-27 oz. (567-765 g) 8 BTDC Model 3.0L Sprk Plug Gp Sprk Plug Type Firing Order.035 In. (0.9 mm) AC-MR43T NGK-BR6FS Chmpion RV15YC4 Specifictions Coil Description Specifiction Coil Prt Numer 392-7803A4 Mx. Operting Amps* 1.1 Primry Resistnce 1.1-1.5 Ohms Secondry Resistnce 9.400-11.700 Ohms Secondry Continuity* 67-77 Resistor Wire 1.8-2 Ohms Firing Order 1-3-4-2 50683 4B - 2 - IGNITION SYSTEM 90-816462 2-695
Distriutor Advnce Curves MCM 3.0L with Prestolite Distriutor Distriutor Advnce: 16 Initil Timing: 8 BTDC Totl Advnce: 24 @ 4100 RPM Point Gp:.016 in. (0.41 mm) Point Dwell: 39-45 Point Spring Tension: 20-27 oz. (567-765 g) IMPORTANT: Distriutor dvnce curve chrts do not include the initil engine timing. Bsic initil timing must e dded to chrt for totl dvnce curve. IMPORTANT: The sprk dvnce is controlled y the ignition module. 35 30 TOTAL SPARK ADVANCE MINUS INITIAL TIMING 25 20 15 MAX. MIN. 10 5 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 ENGINE R.P.M. 70808-3 90-816462 2-695 IGNITION SYSTEM - 4B - 3
Precutions! WARNING When performing the following procedure, e sure to oserve the following: Be sure tht engine comprtment is well ventilted nd tht no gsoline vpors re present, to void the possiility 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 ttery cle connections. System is negtive ( ) ground. Do not disconnect ttery cles while engine is running. Sprk Plugs 1. Inspect ech plug individully for dly worn electrodes, glzed, roken or listered porcelin nd replce plug where necessry. 2. Inspect ech sprk plug for mke nd het rnge. All plugs must e the sme mke nd numer or het rnge. Refer to Specifictions for sprk plug numers. 3. Adjust sprk plug gps with round feeler guge. e IMPORTANT: Tpered set sprk plugs re not interchngele 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 15 l. ft. (20 N m.). Het trnsfer nd gs-tight sel must e chieved. Sprk Plug Wires 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 oots. 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. Distriutor Cp nd Rotor 6. Loosen distriutor cp retining screws. 7. Remove distriutor cp. 8. Clen cp with wrm sop nd wter nd low off with compressed ir. 9. Check cp contct for excessive urning or corrosion. Check center contct for deteriortion. IMPORTANT: Distriutor cps (for mrine use) should hve rss contcts, luminum contcts should not e used. Sprk Plug Detil c f d 50674 - Porcelin Insultor - Check For Crcks In This Are of Porcelin c - Shell d - Proper Gp e - Side Electrode (Bend to Adjust Gp) f - Center Electrode (File Flt When Adjusting Gp) - Do Not. Bend 10. Check cp for crcks or cron trcks using mgneto nlyzer. 11. Remove rotor. 12. Check for urned or corroded center contct. 13. Check rotor for crcks nd cron trcks using mgneto nlyzer. 14. Instll rotor on shft. Be sure rotor is completely seted on shft. 15. Plce cp on distriutor. 16. Tighten retining screws securely. 4B - 4 - IGNITION SYSTEM 90-816462 2-695
Contct Points 1. Exmine contct points for dirt, wer, pitting nd mislignment. Dirty points should e clened. Norml point condition is n overll grey color on contct surfce. 2. Check for point resistnce. A voltge drop of less thn.125 volts cross points should exist. Mke this check with sensitive volt meter or point resistnce meter. ABNORMAL POINT WEAR 1. Points, which hve een operted for period of time, hve rough surfce, ut this my not men tht points re worn out. 2. If points urn or pit, however, they soon ecome unstisfctory for further opertion. Not only must they e replced, ut ignition system nd engine must e checked to determine cuse nd elimintion of troule. Unless condition is corrected, new points will provide no etter service thn old points. CLEANING POINTS 1. Dirty contct points should e dressed with few strokes of clen, fine -cut contct file. File should not e used on other metls nd should not e llowed to ecome gresy or dirty. IMPORTANT: Never use emery cloth to clen contct points. 2. High voltge cuses excessively high current flow thru contct points which urns them rpidly. High voltge cn result from improperly djusted or inopertive voltge regultor. 3. Oil or crnkcse vpors, which work up into distriutor nd deposit on point surfces, cuse them to urn rpidly. 4. If contct point opening is too smll (cm ngle too lrge), points will e closed too long. Averge current flow thru points will e too high, so points will urn rpidly nd rcing will occur etween points. 5. High series resistnce in condenser circuit will prevent norml condenser ction, so contct points will urn rpidly. This resistnce my e cused y loose condenser mounting or led connection, or y poor connections inside condenser. PITTED POINTS 1. Contct point pitting results from n out-of-lnce condition in ignition system which cuses trnsfer of mteril from one point to other so tht tip uilds up on one point while pit forms in other. + 2. Contct surfces, fter considerle use, my not pper right nd smooth, ut this is not necessrily n indiction tht they re not functioning stisfctorily. Do not ttempt to remove ll roughness nor dress point stisfctorily. Do not ttempt to remove ll roughness nor dress point surfces down smooth. Merely remove scle or dirt. 3. Bdly urned or pitted contct points should e replced nd cuse of troule determined nd corrected. + BURNED POINTS 1. Contct point urning results from high voltge, presence of oil or other foreign mteril, defective condenser nd improper point djustment. Mteril Trnsfer - Negtive to Positive - Positive to Negtive 2. If points re pitted, replce condenser (nd points). 90-816462 2-695 IGNITION SYSTEM - 4B - 5
Replcement 1. Remove primry nd condenser led wires from contct point terminl. 2. Remove contct set ttching screw nd lift contct point set from reker plte. 3. Clen oil smudge nd dirt from reker plte. 8. Check point spring tension (20-27 oz.) 567-765g. IMPORTANT: Crefully wipe protective film from point set prior to instlltion. 4. Plce smll mount of Distriutor Cm Luricnt on distriutor cm. 5. Plce new contct point ssemly in position on reker plte nd instll ttching screw. 6. Check points for proper lignment. If points do not lign properly, replce with nother set of points. 50641 - Lterl Mislignment - Proper Lterl Alignment 7. Connect primry nd condenser led wires to terminl on contct point set. - Movle Contct - Spring Tension Guge Contct point pressure must fll within specified limits (Step 8, preceding ). Wek tension will cuse chtter which results in rcing nd urning of points nd n ignition miss t high speed, while excessive tension will cuse undue wer of contct points, cm nd ruing lock. Contct point pressure should e checked with spring guge. Scle should e hooked to reker lever, nd pull exerted t 90 to reker level. Reding should e tken just s points seprte. Pressure cn e djusted y ending reker level spring. If pressure is excessive, it cn e decresed y pinching spring crefully. To increse pressure, remove lever from distriutor so tht spring cn e ent wy from lever. Avoid excessive spring distortion. IMPORTANT: Point gp or (dwell) cn e djusted y 2 methods. It is preferred tht points e djusted with feeler guge, then checked with dwell meter. Points, however, lso cn e djusted, s well s checked, with dwell meter: After points hve een set, dwell should e checked with engine running. 4B - 6 - IGNITION SYSTEM 90-816462 2-695
POINT ADJUSTMENT WITH FEELER GAUGES 1. Rotte distriutor until ruing lock rests on pek of cm loe, which will provide mximum reker point opening. 2. Insert correct feeler guge etween reker points. 3. Loosen lock screw nd djust points to.016 in. (0.5mm). IMPORTANT: Cm ngle increses s point opening is decresed nd vice vers. 50654 - Lock Screw 27045 DWELL ADJUSTMENT 1. Remove distriutor cp nd rotor. 2. Connect positive (+) dwell meter led to negtive ( ) side of coil. Connect negtive ( ) meter led to ground. 3. Loosen point lock screw slightly. 4. While crnking engine with strter, djust dwell with screwdriver to otin reding on dwell meter, s specified in Specifictions, nd tighten lock screw. (Dwell reding will e unstedy using this method.) Cm Angle - Cm - Direction or Rottion c - Breker Points d - Dwell (In Degrees When Points Are Closed) e - Points Open 5. Instll rotor nd distriutor cp nd recheck dwell with engine running. IMPORTANT: Dwell should e checked etween idle nd 1750 RPM. Any dwell reding vritions of more thn 3 etween idle nd 1750 RPM would indicte wer in the distriutor. Cm ngle redings, tken t speeds ove 1750 engine RPM, my prove unrelile on some dwell meters. 90-816462 2-695 IGNITION SYSTEM - 4B - 7
Condenser 1. Use Mgneto Anlyzer for test. 2. Test condenser for the following:. Condenser cpcity test (.18-.25 mfd).. Condenser lekge nd short test. c. Condenser series resistnce test. 3. Replce condenser if test results re not within specifictions. Coil 1. Use Mgneto Anlyzer for test. 2. Check coil for the following:. Coil power test.. Coil surfce insultion test. c. Coil continuity test. d. Primry resistnce test. e. Secondry resistnce. 3. Replce coil if test results re not within specifictions. Ignition Resistnce Wire Distriutor Repir Removl 1. Disconnect distriutor primry led from coil terminl. 2. Remove distriutor cp nd rotor. IMPORTANT: If necessry to remove leds from distriutor cp, mrk position on cp tower for led to numer 1 cylinder. This will id in instlltion of leds in cp. 3. Scrie relignment mrk on distriutor in line with rotor notch (locted on distriutor shft). 4. Mrk distriutor housing in reference to engine lock. 5. Remove olt nd hold-down clmp nd remove distriutor. IMPORTANT: Avoid rotting engine with distriutor removed, s ignition timing will e upset. e (ELECTRIC CHOKE) 1. Disconnect wire from positive (+) side of coil. 2. Unplug quick disconnect (with 2 wires) from electric choke heter element. 3. Connect ohmmeter leds to ends of disconnected wire. Replce resistor wire if reding is not within specifictions. 4. Reconnect wires to coil nd choke. 5. Breker Point Ignition Models: For instructions on replcing resistor wire, refer to Section 4, Prt E. c d 27045 Breker Plte And Attching Prts - Rotor Alignment Flt - Breker Plte c-breker Point Attching Screw d - Condenser Brcket With Screw e-wire Terminl With Screw 4B - 8 - IGNITION SYSTEM 90-816462 2-695
Disssemly IMPORTANT: It is not necessry to disssemle distriutor ny further thn required to complete repirs. 1. Remove condenser nd reker points from reker plte. Test condenser nd check reker points. 2. Remove reker plte from distriutor housing. Excessive oil on reker plte ssemly would indicte d oil sel in distriutor housing. IMPORTANT: Min shft ushings nd oil sel in housing re not serviced seprtely. Housing, ushings nd oil sel re serviced s complete ssemly. 3. Remove roll pin retining driven ger to min shft nd slide ger from shft. 4. Check for side ply etween min shft nd ushings in distriutor housing. Mximum side ply llowed is.002 in. (0.05 mm). 5. Remove shft from housing nd check shft for eing ent with dil indictor nd V-locks. Mximum runout is.002 in. (0.5 mm). 6. Remove weight cover, check weights nd weight stop for wer. Check weights for free movement on pins. Advnce Weights nd Components Ressemly 1. Replce centrifugl dvnce, s necessry. 2. Luricte shft with engine oil. Instll min shft in distriutor housing. 3. Instll driven ger on min shft. 4. Line up mrk on driven ger with rotor tip on min shft. 5. Instll roll pin through ger nd min shft. 6. Instll reker plte on distriutor housing. 7. Instll condenser nd reker points on reker plte. 8. Instll rotor. 9. Instll distriutor s outlined in Distriutor Instlltion following. d c Ger Instlltion - Rotor Contct - Ger Alignment Mrk 74551 74551 - Weight Cover - Weight Springs c - Weights d - Weight Stop Studs 90-816462 2-695 IGNITION SYSTEM - 4B - 9
Distriutor Instlltion Engine Not Distured 1. Instll new gsket on distriutor housing. 2. Turn rotor pproximtely 1/8 turn in counterclockwise direction pst mrk previously scrtched on distriutor housing. 3. Work distriutor down into position in engine lock with distriutor positioned s noted during removl. IMPORTANT: It my e necessry to move rotor slightly to strt ger into mesh cmshft ger, ut rotor should line up with mrk when distriutor is down in plce. Distriutor shft must enter oil pump shft for complete instlltion. 4. Replce nd tighten distriutor hold-down olt nd clmp. Connect primry led to coil. Also instll sprk plug nd coil secondry wires, if removed. IMPORTANT: Wires must e instlled in supports, to prevent cross-firing. Firing order is 1-3-4-2. 5. Set points gp to.016 in (0.5 mm). 6. Instll rotor 7. Check dwell (39-45 degrees) 8. Time ignition s outlined under IGNITION TIM- ING. Engine Distured 1. Locte No. 1 piston in firing position y either of two methods descried elow.. 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. 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 distriutor to opening in lock in norml instlled ttitude. 3. Position rotor to point towrd front of engine (with distriutor housing held in instlled ttitude), then turn rotor counterclockwise pproximtely 1/8-turn more to the left nd push distriutor down to engge cmshft. It my e necessry to rotte rotor slightly until cmshft enggement is felt. 4. While pressing down firmly on distriutor housing, engge strter few times to mke sure oil pump shft is engged. Instll hold-down clmp nd olt nd snug up olt. 5. Turn distriutor ody slightly until points just open nd tighten distriutor clmp olt. 6. Plce distriutor cp in position nd check tht rotor lines up with terminl for No. 1 sprk plug. Instll cp. 7. Instll cp, distriutor primry led to coil. Check nd connect sprk plug wires, if they hve een removed. Wires must e instlled in their proper loction in supports to prevent cross-firing. Firing order is 1-3-4-2. 8. Set points gp to.016 in (0.5 mm). 9. Instll rotor 10. Check dwell (39-45 degrees) 11. Time ignition s outlined under ignition Timing. Ignition Timing 1. Connect timing light to No. 1 sprk plug. Connect power supply leds on light to 12 volt ttery. Refer to Specifictions for cylinder numering nd loction. 2. Connect tchometer to engine. 3. Strt engine nd run t norml idle speed. 4. Aim timing light t timing t, locted on timing ger cover nd crnkshft torsionl dmper. 4B - 10 - IGNITION SYSTEM 90-816462 2-695
IMPORTANT: GM engine timing mrks (on t) re in 2-degree increments. Timing must e set on the efore side of 0 (Top Ded Center). 72328 - Degree Mrks - Timing Mrk 5. Adjust timing y loosening distriutor clmp nd rotting distriutor ody s required until timing mrk on dmper or pulley lines up with the mrk on t specified in Specifictions. Tighten clmp nd recheck loction of timing mrk. 6. Stop engine nd remove timing light. 90-816462 2-695 IGNITION SYSTEM - 4B - 11
(DDIS) Digitl Distriutorless Ignition System Specifictions COIL Description Specifiction Primry Resistnce 1.9-2.5 Ohms *1 Secondry Resistnce 11.3-15.5 Ohms *2 * At Room Temperture 68 F (20 C) 1 Ohmmeter scle Rx1 2 Ohmmeter scle Rx1000 IGNITION TIMING Timing FIRING ORDER FRONT 8 BTDC t 700 RPM Tools/Luricnts/Selnts Mercury Mrine Specil Tools Description Prt Numer Dwell Meter 91-59339 Mgneto Anlyzer 91-76032 Remote Strter Switch 91-52024A1 Timing Light 91-99379 Volt/Ohm Meter 91-99750 Timing Jumper 91-818812A1 Sprk Plugs Sprk Plug Gp 3.0L (DDIS) 3.0LX (DDIS).035 In. (0.9 mm) AC-MR43T NGK-BR6FS Chmpion RV15YC4 AC-MR43LTS NGK-BPR6EFS Chmpion RS12YC IGNITION COIL Overspeed Prevention Control 1-3-4-2 Torque Specifictions 50653 CONTROL MODULE FUNCTION SPECIFICATIONS ENGINE SPEED (RPM) SPARK CONTROL FUNCTION 4750 Norml Sprk 5050 Misfires - Intermittent Sprk 5150 Sprk Shuts OFF, completely NOTE: Refer to SECTION 1-C for trouleshooting Fstener Loction In. Ft. L. Ft. N m Motion Sensor Clmp 3/8-16 20 27 Ignition Amplifier 65 7.3 Ignition coils 20 2.2 Sprk Plugs (14 mm) 15 20 4B - 12 - IGNITION SYSTEM 90-816462 2-695
Description The Digitl Distriutorless Ignitions System (DDIS) replces the conventionl point style ignition system. A motion sensor replces the conventionl distriutor nd senses crnkshft position. The ignition mplifier controls coil output, sprk dvnce, nd limits engine speed to pproximtely 5000 RPM. The ignition coil is ctully two coils in one with four high voltge towers. The coils re fired on oth compression stroke nd exhust stroke. DDIS System Components MCM 3.0L/3.0LX Models IGNITION COIL IGNITION AMPLIFIER MOTOR SENSOR 50402 IMPORTANT: Models equipped with Digitl Distriutorless Ignition System (D.D.I.S.) hve n overspeed prevention control uilt into the system. The control module limits engine speed to 5000 RPM, when speed exceeds 5000 RPM, the control misfires ignition sprk nd continues to slow down engine until engine speed drops elow 4800 RPM. When the engine exceeds 5100 RPM, primry pulses to the ignition coil stop until engine speed drops elow 5000 RPM. 90-816462 2-695 IGNITION SYSTEM - 4B - 13
Sprk Advnce Control IMPORTANT: The ignition mplifier controls sprk dvnce ove 1000 RPM. There is no djustment. Initil timing must e set elow 1000 RPM. NOTE: Mny timing lights re inccurte t high engine speeds; therefore, timing should not e djusted ove 1000 RPM. Module Prt Numer: 18811T1 Module Advnce: 18 Initil Timing: 8 BTDC Totl Advnce: 26 Advnce Curve Chrt (Reference Only) IMPORTANT: Advnce curve chrts do not include the initil engine timing. Bsic initil timing must e dded to chrt for totl dvnce curve. EXAMPLE: Advnce curve chrt shows 13 sprk dvnce t 2000 RPM. Add 8 BTDC initil timing for totl sprk dvnce of 21 t 2000 RPM. MCM 3.0 L DDIS MODELS 35 30 TOTAL SPARK ADVANCE MINUS INITIAL TIMING 25 20 15 MAX. MIN. 10 5 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 ENGINE R.P.M. 70808-4 4B - 14 - IGNITION SYSTEM 90-816462 2-695
Sprk Advnce Control IMPORTANT: The ignition mplifier controls sprk dvnce ove 1000 RPM. There is no djustment. Initil timing must e set elow 1000 RPM. NOTE: Mny timing lights re inccurte t high engine speeds; therefore, timing should not e djusted ove 1000 RPM. Module Prt Numer: 18811T2 Module Advnce: 18 Initil Timing: 8 BTDC Totl Advnce: 26 Advnce Curve Chrt (Reference Only) IMPORTANT: Advnce curve chrts do not include the initil engine timing. Bsic initil timing must e dded to chrt for totl dvnce curve. EXAMPLE: Advnce curve chrt shows 8 sprk dvnce t 2000 RPM. Add 8 BTDC initil timing for totl sprk dvnce of 16 t 2000 RPM. MCM 3.0 LX (DDIS) MODELS 35 30 TOTAL SPARK ADVANCE MINUS INITIAL TIMING 25 20 15 MAX. MIN. 10 5 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 ENGINE R.P.M. 70808-5 90-816462 2-695 IGNITION SYSTEM - 4B - 15
Components Tests IMPORTANT: Check sprk plugs nd sprk plug wires efore the DDIS system. Use Multi-Meter 91-99750 to test DDIS components.! WARNING When performing the following procedures, e sure to oserve the following: Be sure tht engine comprtment is well ventilted nd tht no gsoline vpors re present, to void the possiility of fire. Be sure to keep hnds, feet, nd clothing cler of moving engine prts. Do not touch or disconnect ny ignition system prts while engine is running. Do not reverse ttery cle connections. System is negtive ( ) ground. Do not disconnect ttery cles while engine is running. 2. Disconnect engine hrness form ignition mplifier. With ignition switch in the RUN position, check voltge t terminl from engine hrness. Reding should e ttery voltge. - Check Voltge Here 3. If voltge redings in steps one nd two differ more thn pproximtely 1/2 volt, ignition mplifier is defective. Ignition Amplifier 1. Disconnect ignition mplifier form coil. With the ignition switch in the RUN position, check voltge t terminl from ignition mplifier. Reding should e ttery voltge. - Check Voltge Here 4B - 16 - IGNITION SYSTEM 90-816462 2-695
Ignition Coil NOTE: Ignition switch must e in the OFF position when testing ignition coil. 1. Primry coil resistnce:. Disconnect coil from ignition mplifier.. Mesure resistnce etween coil connector terminls s shown.. Mesure resistnce etween towers s shown. 3 2 4 1 74672 * At Room Temperture 68 F (20 C) 1 Ohmmeter set on the Rx1000 Scle - Check Resistnce From to - Check Resistnce From to c TERMINALS to to c c RESISTANCE RANGE 19-1.9 2.5 Ohms * 1 HIGH VOLTAGE TOWERS 1 to 4 2 to 3 RESISTANCE RANGE 11.3-15.55 Ohms * 1 3. Coil insultion resistnce:. Mesure resistnce etween coil connector terminl nd engine ground. Minimum resistnce - 10 megohms. * At Room Temperture 68 F (20 C) 1 Ohmmeter set on the Rx1 Scle 2. Secondry coil resistnce:. Disconnect sprk plug wires from coil high voltge towers. - Mesure Resistnce Between Here nd Ground 90-816462 2-695 IGNITION SYSTEM - 4B - 17
. Mesure resistnce etween ech high voltge tower nd engine ground. Minimum resistnce - 10 megohms. IMPORTANT: Motion sensor must e t room temperture, 68 F (20 C), when testing. Motion Sensor NOTE: Motion sensor is fctory set nd not djustle. IMPORTANT: Do not remove cover unless it is dmged. There re no servicele prts inside the motion sensor. Replce entire unit if defective. - Check Resistnce Between These Two Points Shift Interrupter Switch 1. Disconnect ignition mplifier from engine hrness. Check for continuity etween hrness connector () nd engine ground. Switch is normlly open. When shifting out of forwrd or reverse, switch will close momentrily. 74537 Motion Sensor 1. With ignition switch in the OFF position, disconnect motion sensor from ignition mplifier. Mesure resistnce etween sensor terminls. Resistnce rnge - 140 to 180 ohms. (Rx10) If resistnce is not within specifictions, replce motion sensor. - Check For Continuity From Here To Ground 4B - 18 - IGNITION SYSTEM 90-816462 2-695
Motion Sensor Removl 1. Disconnect wires (). 2. Align hole [not roll pin hole] in ger with notch on motion sensor housing. Instll new gsket. Apply Quicksilver 2-4-C Mrine Luricnt with Teflon to ger. 74390 - Wires 74537 2. Crnk engine until timing mrk is on zero. 3. Remove motion sensor. IMPORTANT: To simplify motion sensor reinstlltion, do not turn crnkshft with motion sensor removed from engine. - Hole - Notch in Motion Sensor Housing NOTE: When instlling motion sensor it my e necessry to turn oil pump drive shft for lignment with motion sensor drive shft. 3. Remove motion sensor cover. Instll motion sensor so drin hole is opposite engine lock nd sensor is ligned s shown. Instlltion IMPORTANT: After instlltion, pply Liquid Neoprene to ll mounting fsteners nd ground wires of the ignition mplifier nd ignition coil. c NOTE: The DDIS signls the coil to fire on oth compression nd exhust strokes. To instll the motion sensor, numer one piston does not hve to e TDC of its compression stroke. Simply lign the timing mrk on zero. 1. Crnk engine until timing mrk is on zero. - Drin Hole - Towrd Engine Block c - Align These 74538 90-816462 2-695 IGNITION SYSTEM - 4B - 19
4. Reinstll cover. Tighten screws securely. 5. Connect wires. 3. Adjust timing y loosening clmp nd rotting motion sensor, s required, until timing mrk on pulley ligns with 8 BTDC mrk on t. Torque clmp olt to 20 l. ft. (27 N m), nd recheck loction of timing mrk. 4. Stop engine nd disconnect timing light. IMPORTANT: GM engine timing mrks (on t) re in 2 increments. Timing must e set on the BE- FORE (Advnce) side of 0 (Top Ded Center). 26549 - Connect Wires DDIS Ignition Timing 1. Connect timing light to No.1 sprk plug. Connect power supply leds on light to ttery.! CAUTION If the following procedure is performed out of wter, wter source must e supplied to the wter intke openings in ger housing. 2. Strt engine nd run t norml idle speed (under 900 RPM - use tchometer in ot instrumenttion). Timing Mrks on GM 4-Cylinder Engines - Timing Mrk - Degree Mrks 72328 4B - 20 - IGNITION SYSTEM 90-816462 2-695
Delco EST Ignition Torque Specifictions Fstener Loction L. Ft. N m Distriutor Clmp 3/8-16 20 27 Sprk Plugs (14 mm) 15 20 Tools/Luricnts/Selnts Mercury Mrine Specil Tools Description Prt Numer Dwell Meter 91-59339 Mgneto Anlyzer 91-76032 Remote Strter Switch 91-52024A1 Timing Light 91-99379 Volt/Ohm Meter 91-99750 Timing Jumper 91-818812A1 Liquid Neoprene 92-25711-1 Module Tester Kent-Moore Tools Kent-Moore Specil Tools 29784 Little Mck Roseville, MI 48066 Phone: (313) 574-2332 J24642 Tools/Luricnts Otined Loclly Point Spring Tension Guge Distriutor Cm Luricnt Specifictions Timing (At Idle RPM) EST Ignition* 1 BTDC Sprk Plugs Sprk Plug Gp 3.0L 3.0LX GM 4-Cylinder In-line Firing Firing Order 1-3-4-2.035 In. (0.9 mm) AC-MR43T NGK-BR6FS Chmpion RV15YC4 AC-MR43LTS NGK-BPR6EFS Chmpion RS12YC 50683 Description EST or Electronic Sprk Timing is High Energy Ignition System (HEI). The distriutor itself hs no centrifugl dvnce mechnism or devices. The sprk plug wires re cron-impregnted cord conductor with silicone ruer jcket. It is importnt they e hndled with cre, nd routed so s not to cross ech other, or to e in contct with other prts of the engine to prevent ruing. The EST System uses squre coil with epoxy covered windings to protect ginst moisture nd rcover. * Timing must e set using specil procedure s outlined in this section. Timing cnnot e properly set using the conventionl method. 90-816462 2-695 IGNITION SYSTEM - 4B - 21
The timing cnnot e set the sme wy tht other ignition systems were. d c e 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 y MerCruiser (one for the shift interrupt nd two white leds re used to freeze dvnce for properly setting initil timing). Inside the distriutor, the pick-up coil ttches to the module t molded prong connector. g h e f 70106 d - Distriutor with Sprk Plug Wires - Wires (WHITE) Used in Timing Procedure c - Wire from Shift Interrupt Switch d - Distriutor Hrness e - Engine Hrness Wire (PURPLE AND GRAY) f - Coil EST uses mgnetic pulse genertor nd n electronic module to primry circuit current. Internlly the Pulse Genertor, or mgnetic pick-up ssemly, tkes the plce of conventionl points. A timer core on the min shft of the distriutor hs externl teeth which lign with n equl numer of pole piece teeth (four for four cylinder engine). The electronic module is smll enough to llow it to e mounted inside the distriutor, nd contins the circuits necessry for dwell control nd dvnce of the timing. f - Mgnetic Pulse Genertor - 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 c 70107 4B - 22 - IGNITION SYSTEM 90-816462 2-695
Component Tests The following tests cn e mde with the distriutor nd coil mounted on or off the engine. The test procedures will check ech component of the distriutor nd ignition coil. Distriutor cp nd rotor should e checked for corrosion, crcks, cron trcks or wer. Replce if needed. 5. Set ohmmeter to Rx100 high scle. Connect ohmmeter to 12 volt terminl () nd to coil high tension post (). Reding should e etween 7800 nd 8800 ohms. If it reds outside of this rnge, replce coil. Testing Pickup Coil In order to test the module, n pproved module tester, such s Kent-Moore Tester, (J24642 or equivlent), must e 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 e inspected nd clened if needed. Testing Ignition Coil e c d c d - Connector - GREEN Led c - WHITE Led d - Distriutor Housing 70105 f 70104 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 distriutor. NOTE: Upon reinstlltion, first instll lck connector (distriutor hrness) to coil. Then instll gry connector (engine hrness). 2. Set ohmmeter to Rx100 scle nd connect one led to 12 volt terminl () of coil nd the other led to ground (d), ny clen metl on the coil frme. Reding should e infinite. If not, replce coil. 3. Set ohmmeter to Rx100 scle nd connect to 12 volt terminl () nd terminl (c). Reding should e pproximtely.4 ohms. If not, replce coil. 4. Set ohmmeter to Rx1 scle nd connect to 12 volt terminl () nd tchometer terminl (f). Reding should e pproximtely.4 ohms. If not, replce coil. 1. Remove distriutor cp. 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 distriutor housing. Reding should e infinite. If not, replce pickup coil. 4. Repet Step 3 with ohmmeter connected to GREEN led. Reding should e infinite. If not, replce pickup coil. 5. Set ohmmeter to Rx100 scle. Connect ohmmeter to GREEN nd WHITE pickup coil leds. Reding should e constnt, unchnging vlue in the rnge of 500-1500 ohms. If not, replce pickup coil. Be certin to flex leds y hnd during this test to locte possile intermittent open circuits (loss of continuity). If ny exist, replce pickup coil. 90-816462 2-695 IGNITION SYSTEM - 4B - 23
Module Prt Numer: 811637 Module Advnce: See Notice Initil Timing: 1 BTDC Totl Advnce: 23 MCM 3.0L, 3.0LX with EST 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 ENGINE R.P.M. 70808-15 4B - 24 - IGNITION SYSTEM 90-816462 2-695
Timing Procedure IMPORTANT: Filure to follow the timing procedure instructions will result in improper timing cusing performnce prolems nd possile severe engine dmge. 1. Strt engine nd llow to rech operting temperture. 2. With engine running, instll jumper wire cross the two WHITE leds on the distriutor using (91-818812A1), or fricte one using 6 in. (150 mm) section of 16 guge wire with two mle ullet terminl ends connected. 3. Bypss the shift interrupt switch y disconnecting wires t shift interrupt switch. Temporrily join the engine hrness wires together. IMPORTANT: Do not fil to reconnect these two wires to the shift interrupt switch when timing procedures re complete. 4. With timing light connected, check timing. Timing should e 1 BTDC. 5. If required, loosen distriutor hold down clmp nd rotte distriutor to otin specified timing. 6. Secure distriutor hold down clmp, nd recheck timing s ove. 7. Reconnect the two wires to the shift interrupt switch. Remove jumper wire t distriutor white leds. IMPORTANT: Be sure to remove jumper wire efore returning engine to service, otherwise timing will not dvnce. 8. With timing light still connected, nd engine t IDLE, verify tht timing did dvnce to 12 BTDC, (plus or minus 2 ). At 2400-2800 RPM mximum (totl) dvnce is otined nd should e 27 BTDC (plus or minus 2 ). 70103 - WHITE Leds - Jumper Led 90-816462 2-695 IGNITION SYSTEM - 4B - 25