Just Luv Workin on Skis
Member
Ran great, then after sitting for a break it would crank but not start. Once home checked for spark; sometimes sparks, sometimes doesn’t but never started again. Here’s what I checked.
787 engine. Ignition circuit has: coil directly connected to MPEM and MPEM directly connected to trigger coil; does not have CDI unit or holder relay.
Battery 12.6 volts (will crank for a long time).
Squirted mixed gas directly into cylinders and cranked several times; also squirted directly into airbox (tries to fire once in a while but never starts).
New spark plugs (also tried with old ones) BR8ES.
Compression: Mag side 135 PTO side 140.
All electrical connections are extremely clean in both front and rear electrical boxes (not a hint of corrosion).
Spark plug boots: 5633 and 5164 Ohms. Also tried cranking while holding capless plug wire with safety pin pushed into the end, near to ground (with bare hand); didn’t get any spark that time (getting brave I know).
Ignition coil secondary winding: 13.02 Ohms
Ignition coil primary winding: 0.5/0.6 Ohms
Trigger coil: 251 Ohms.
Put test light on white (hot) lead to ignition coil while cranking; sometimes lights extremely dimly, sometimes not at all. Traced this wire to front electrical box (where it connects to MPEM and repeated the test with the same results (verified good ground of course).
Disconnected trigger coil wiring inside front electrical box (where it connects to MPEM) and placed test light between Yellow/White hot and Black/Yellow ground; cranked, did not illuminate test light. Also tried this with a Voltmeter and shows 0 to 0.2 volts. Then set range to millivolts and meter showed over range error.
I have both the Clymer’s and Sea Doo manuals and neither give much information on troubleshooting; they just say to use the Sea Doo ignition tester, which I don’t have.
This has happened twice before, but those times it re-started after the engine cooled; this time I wasn’t so lucky.
Sorry for being long, but I tried to be thorough.
787 engine. Ignition circuit has: coil directly connected to MPEM and MPEM directly connected to trigger coil; does not have CDI unit or holder relay.
Battery 12.6 volts (will crank for a long time).
Squirted mixed gas directly into cylinders and cranked several times; also squirted directly into airbox (tries to fire once in a while but never starts).
New spark plugs (also tried with old ones) BR8ES.
Compression: Mag side 135 PTO side 140.
All electrical connections are extremely clean in both front and rear electrical boxes (not a hint of corrosion).
Spark plug boots: 5633 and 5164 Ohms. Also tried cranking while holding capless plug wire with safety pin pushed into the end, near to ground (with bare hand); didn’t get any spark that time (getting brave I know).
Ignition coil secondary winding: 13.02 Ohms
Ignition coil primary winding: 0.5/0.6 Ohms
Trigger coil: 251 Ohms.
Put test light on white (hot) lead to ignition coil while cranking; sometimes lights extremely dimly, sometimes not at all. Traced this wire to front electrical box (where it connects to MPEM and repeated the test with the same results (verified good ground of course).
Disconnected trigger coil wiring inside front electrical box (where it connects to MPEM) and placed test light between Yellow/White hot and Black/Yellow ground; cranked, did not illuminate test light. Also tried this with a Voltmeter and shows 0 to 0.2 volts. Then set range to millivolts and meter showed over range error.
I have both the Clymer’s and Sea Doo manuals and neither give much information on troubleshooting; they just say to use the Sea Doo ignition tester, which I don’t have.
This has happened twice before, but those times it re-started after the engine cooled; this time I wasn’t so lucky.
Sorry for being long, but I tried to be thorough.