5.8L OMC surge midrange

[airdvr1227]

New one today. Took her out on Lake Erie. After running at 4000rpm's from Put-in-Bay over to Kelley's Island she started surging at about 2000rpm. Lower than that and she ran rough, above 2000 it seemed OK.

That was the hardest and longest run for my boat yet. It was a good 20 minutes. Wasn't choppy but was like glass either. My first thought was maybe I kicked up some junk in the fuel tank. But it ran good above 2000. Strange. Some guidance on what to look at first wouuld be appreciated.

 

[Bifflefan]

Re: 5.8L OMC surge midrange

surging is a lean condition. you may have a little piece of something in one of the passages or one of the air bypass'.
It may pass. look at the top of the carb by the venturee's if it a holly there are 4 small holes behind the rear ones and 4 in front of the front ones. see if there is a piece fo dirt or something in one of them.
On a Q-jet i cant remember if they are there or not, but they are somewhere up around there i think.
a little blast of shop air should knock it out. if not try a little fuel treatment/ cleaner to see if that helps.

 

[airdvr1227]

Re: 5.8L OMC surge midrange

Thanks. I'm thinking new fuel filter at the least.