2008 Mercury Optimax EFI 115 Problems at low RPMs

keltonme

Recruit
Joined
Jul 2, 2011
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1
Hello,
I have a 2008 Mercury Optimax EFI, 115 HP outboard. It ran fine for most of the day today. We docked it, came out, and tried to idle out and it started acting up.

At idle speeds under approx 2500 rpm the engine pulses/stutters and eventually stalls. It also won't idle in neutral. Here's what we found looking around.....the air filter (looks like a K&N type) was disintegrated and parts were missing. It's like it melted and turned into a goo. We removed the old filter and retrofited it with a pair of boxers (little McGuyver action). It smelled strong of gas around the air filter, and at one point had some gas dripping out.

Also, I pulled one of the spark plugs and it appears to be a little dark on the ends (they're 3 years old, and don't look that bad). From what I could tell on line, it means that the mixture may be too rich?

I just changed the oil and the impeller a month ago. When I first bought this boat, it did something like this (on a much minor scale, and lasted for 10 minutes or so) The dealer said they checked it over and nothing was wrong. It did this a handful of times after (maybe 3).

Any ideas on what I could do to fix it?
 
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