OMC loses power... fuel cut / rev limit problem?

[reavesga]

Re: OMC loses power... fuel cut / rev limit problem?

Long turns ie lots of cranking? If this is the case and you know you havegood spark then. Check the fuel and carb. Even after sitting for a couple of weeks my 40 year 3.0 fires right up with just a couple of pumps on the throttle. Starter is engaged for only a few seconds. I am still betting your problem is in the carburator.

I do recommend changing to breakerless ignition. Will eliminate a lot of the what ifs.

 

[Joshua Nichols]

Re: OMC loses power... fuel cut / rev limit problem?

Had a similar problem with mine.. I am real picky about the way stuff runs.. Mine has neck snapping holeshot, but would spit the catch back up and spit again and catch back up.. It was super irritating.. Cleaned up the carb.. Solved the issue.. Had some funky in the bottom of the fuel bowl.. Also my spark arrester was filthy.. Looked clean till I took it off.. Belt dust and years of the crankcase venting on it.. The previous owner of my boat I think did more skiing than maintenance.. Anyhow.. She is a screamer now.. I would look into a fuel issue... Good luck

 

[proshine43]

Re: OMC loses power... fuel cut / rev limit problem?

went out with my friend on his new boat, first time on the water with it, and he had the same problem. ran fine under 3500- 4000 rpms but wide open throttle after about a minute to two minutes it goes down 4500, then down to 4000 than 3500. we let it sit for about a minute to make sure its not overheating and the gauge only said 150, and it ran fine. back to open throttle and it does it again. we have no idea what it could be

 

[hushmandco]

Hello
I am not sure if the members are still active after 12 years from the last post…
I have a 5.8 OMC , Ford block, FSI
My engine RPM doesn’t go above 4000 psi while in neutral. When in gear it tops as 3600 -3700
I replaced the distributor cap and the floater arm but still the same results.
Is there any limiter mechanism that relates to engine temperature?

 

[CaptnKingfisher]

Re: OMC loses power... fuel cut / rev limit problem?

Its is most likely fuel. If after going to wide open throttle it loses pwr for a few seconds and then comes right back and keeps power I am guessing the needle valve metering fuel into the bowl of the carb. It can randomly stick and cause this. Vibration shakes it free and all is good again. Before rigging up fuel cans I would have a competent tech put a carb kit in it.

"before"? Rebuild carb before testing the engine on a portable tank? Just my humble opinion as a shade tree mechanic but I always keep a spare fuel tank around for diagnostic purposes. Takes no time or money to try a different tank. Rebuilding a carb is a pain in the ass and often not needed

 

[CaptnKingfisher]

Just realized this is old.

Hello
I am not sure if the members are still active after 12 years from the last post…
I have a 5.8 OMC , Ford block, FSI
My engine RPM doesn’t go above 4000 psi while in neutral. When in gear it tops as 3600 -3700
I replaced the distributor cap and the floater arm but still the same results.
Is there any limiter mechanism that relates to engine temperature?

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