SmurfOnABoat

Well back to the drawing board. The cutting out is getting worse and worse (doing it more frequently with more delay now). I have adjusted floats, cleaned and checked for pinfit on main lug, check all fuel lines.

Wonder if its the Thunderbolt? I eyeballed the gauges as I was going through a series of rollers and it cut out twice for about half a second each and the only gauge to falter is the RPM, it will drop almost completely to zero then back to RPM.

New scenario now, the engine will cut out on clean smooth water, just out of no where cuts out then comes back.

steveh1209

Not on a boat but just had similar problem on a 4x4 of mine. Started cuting off then it would cut out completely and wouldn't restart. Wait 30-45 seconds, start up and go for a while and do it again. Replaced everything, ignition module, distibuter, all kinds of stuff. Last thing was my 12yr old MSD ignition. Problem completly gone for good. So it is a good possibilty the ignition is beginning to fail.

BenPerfected

We had a the same issue. It was a cracked ground wire connection inside the Merc wiring harness about 6-12 " from the main plug. We would hit a wave and it would miss. We finally found it by moving all the wiring around until you hear the miss. Finding the bad connection/loose or cracked wire, etc. is not easy...it took us two years to find it!

articfriends

iTrader: (1)

I had same exact problem last year but my motor is efi,would cut out on big waves,finally found one of the wires in the harness that was bad internally,found it by accident when checking the timing. I bumped a wrench against a ignition wire behind the motor idling and it quit,I had wiggled all of them several times before but just got lucky and finally hit it just right,Smitty