Losses spark after running awhile

Marshalld

Recruit
Joined
Sep 13, 2012
Messages
2
I launched in the morning let warm up at the dock for 15 minutes then took off, ran for 10 minutes or so at 2500-3000 rpm then started backfiring through the carb(qjet) and surging the eventually stalling. I was able to restart, I put it in gear then died again. It wouldn't start again. I lost spark at coil. Next morning I replaced the coil and it fired up. I let it run a 3000 rpm for 15 min at the dock put it in reverse and it almost died. I go to put it in forward and it died and wouldn't restart. No spark at the coil. It is a thunderbolt 4 ignition with alpha out drive. The boat is a 1989 bayliner arriva 2150. If anybody had this happen to them or has seen this before let me know what was wrong. I thank you in advance
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Losses spark after running awhile

Hook up a jumper wire from the positive battery terminal to the + terminal (purple wire) on the coil and see if it keeps running.
If it keeps running, that eliminates all the wiring between the dash and the coil.

What engine is it?
 

Marshalld

Recruit
Joined
Sep 13, 2012
Messages
2
Re: Losses spark after running awhile

Thanks don. The motor is a mercruiser 305 gm. I have been reading a lot of threads and I still need to check to see if I have voltage at the coil + with the key to run and need to check all electrical connections , module plug and so on. The boat runs great when you just fire it off and it will stay running but once you
Put it in gear it will die then it won't start again until it cools down.
 

wellcraft-classic210

Master Chief Petty Officer
Joined
Sep 22, 2010
Messages
839
Re: Losses spark after running awhile

Ignition module & coil would be suspect items if the wiring checks out. They fail sometimes by acting up when warmed up.
 
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