2001 Yamaha F115 won't go above 1800rpm after shutting off after run down river

mdegood

Seaman Apprentice
Joined
Dec 8, 2002
Messages
30
Bought this boat @ 3 years ago and has been eating my lunch ever since. I have had several rounds of the injectors and VST filter getting dirty/clogged. 2 occasions of this didn't even have 4 hours of run time. Local boat house said Ethanol phase seperation, so drained 60 gal's of gas scrubbed entire inside of tank, replaced all fuel lines/bulb and replaced the on board 10 micron filter,cleaned VST filter and injectors again and added a 2 micron rancor canister filter. Took boat for the first time since rework. Good low and mid rpm planed out good, but did 't want go much above 4500-4800 rpm just wanted start loosing power. Fuel bulb was not firm but was 't flat either. After @ 25 minutes was able to go to @ 5400 rpm, thought ok finilly got this fixed. S topped to get some shrimp, engine was shut off for maybe 10 minutes. Started with no issues, got out of no wake zone aND advanced throttle no joy 1800 rpm max. Squeezing fuel bulb made no difference. Anchored and removed cowling fuel cup was full and no apparent issues. Let motor cool off for an hour or so, started up no issues and wold run great with the cowling off rpm would go to 6200 rpm. Anyone got any ideas?
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
"Running great with cowling off" may be an indication of an exhaust leak under cowling.....have you also checked the cowling air intake for obstructions/bird nests, etc.?....
 

mdegood

Seaman Apprentice
Joined
Dec 8, 2002
Messages
30
Ok, well no bird or mud dobber nests, that would have been to easy. I ran it yesterday on the water cuff with the cowling off and could not smell or hear an exhaust leak. Going to have look at book and see where the exhaust leak could be.
 
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