Hard-starting Mercruiser 7.4

Rick

Member
Joined
Nov 13, 2009
RO Number
31784
Messages
21
One of the Mercruiser 7.4 engines on my Carver Santego (3467) 1989 is a little slow to start and hesitates when you throttle up quickly, even after it's warmed up, and sometimes backfires through the carb.

My marina's mechanic said it could be that the exhaust risers have begun to fail, and water was getting back into the engine, although he also said it could be a clogged secondary fuel filter. Quite a big difference there in terms of magnitude.

This boat has one rebuilt (about 90 hours by now) and one almost-new engine (I believe it's the rebuilt one that's having the problem; both look pretty new to me, and no one knew which was which when we bought it through a broker).

I am home right now and have not checked to see if either or both of the risers get appreciably warm after the engine's run for a while. I had thought it might be an ignition problem, but he didn't think so.

We haven't had this boat very long, so I'm still learning my way around on it. Thanks for any suggestions.

Rick
 
you should put this up in the Engine part of the forum, and do a Google search on the forum and you'll come up with all kinds of things it could be.I had trouble like this last year it was a bad gas pump.
 
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