2001 F115 Loses power after being shut down

[mdegood!]

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 racor 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 wasn't flat either. After @ 25 minutes was able to go to @ 5400 rpm, thought ok finilly got this fixed. Stopped 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 would run great with the cowling off rpm would go to 6200 rpm. Anyone got any ideas? Checked air intake for bird/mud dobber nests - none found. Thinking exhaust leak, but hear one with motor running and can't notice any exhaust smell in power head area.

[zenoahphobic]

The key might be first to investigate why it ran 6200 with cowl off. Prima facea air, sure it is not restricted to intake (checked cowling?). If not overheating may be culprit, i.e . engine exposed cooled it enough. How long did it sustain 6200? would it have run all day like that?
Someone will chime requesting codes.

[mdegood!]

6200 rpm

Only for a few seconds, don't usually take WOT and maintain it that way. As far as over heating, I had no indications that it was, but it very well could have been. As far as fault codes, I have never retrieved with a yamaha.

[TownsendsFJR1300]

Not sure about your specific issue BUT some recommendations that should help..

First, get some Yamaha RINGFREE. It works really good at keeping the fuel system clean. You can run it at 2x the recommended mix. Its expensive but reg mix is 1 oz/ 10 gallons. I've run it heavier than that on some engines with great results... I run it in EVERY GAS ENGINE I own...

Do NOT run ethonol fuel, pay the extra $ for non-ethonol, its worth it.

Now that your tank is cleaned out of crap, run some K100

Demonstration | Fuel Additive | K-100

Fuel Treatment, Fuel and Gas Additive | K-100 HOME

https://www.yamahapartsandaccessorie...?b=Search&d=34

Any moisture that collects in your tank is suspended in the fuel and burned off as the engine runs.

I've had water in the VST, drained it. Began using non-ethonol, K100 (already was running Ringfree) and over time, NO more visable water, cloudy fuel, etc. I have the original fuel tank in the boat (18 years old, NEVER DRAINED, CLEANED-50 or 60 gallon)