Sick Yamaha F115

[PierBridge]

2001 115 Four Stroke seems short on power, runs smooth until about 3900 then sounds almost like the rev limiter is trying to kick in, when cool isn't as bad but still gutless. Runs at 4500 to 5500 sometimes. New plugs, gas and fuel filter, ran Yamaha ring free and it helped over what it sounded like before. About 300 hrs a year, any thoughts or ideas before my bringing it in?

 

[bossee]

Re: Sick Yamaha F115

Hi,<br />Do You use a fuel/water separator (?? micron)?<br />If You do not use such separator chances are it could be the injectors that are not clean (enough) but that is only a guess.<br />I do not know how fine filters can be used in a fuel/water separator but 10 micron filter is rather common (I have that on my F115). I'm talking about an external fuel/water separator, like this:<br /> Link <br /><br />If the injectors are suspected I do not think You can clean them Yourself, a professional probably need to do it (but I do not think You need to buy new in such case).<br /><br />I would also check the spark plugs are OK (correct make and model plus correct gap) and that it is actually spark on all plugs.<br />A compression test on all cylinders could also be a good thing to perform. Just the easy things first.<br /><br />What prop do you use (diam x pitch)?<br />What is max RPM at full throttle (when it runs OK)? 5500 RPM? It should be preferably close to 6000 RPM.