Yamaha engine help

Jsparks987

Recruit
Joined
Oct 25, 2007
Messages
5
Hi all looking for advice, I had brought a 22ft (seawolf) WA with a 1995 225 Yamaha on a bracket. I believe the boat sat for a year prior to me buying it. This past summer had some problems. The first problem was poor running and sudden shut downs. On the advice of a mechanic I had the tank emptied and clean as well as the lines and filters to the engine changed plus the fuel separator. Still had issues with lack of fuel. I replace the valve just past the VST twice. This was a temporary fix. I clean the pressure regulator and think I have now resolved most of fuel issues. However the engine tops out at 4400rpms wot with correct trim. PSI in all six cycle are low 65,70,65,65,60,65, She starts right up and idles well and seems to be running well, but I feels it isn't running at top speed, at 4400rmps I?m running about 33-36mph on GPS. Any advice where to look now? People have suggested decarbonize. The boat is now laid up for the winter and would like pick your collective brains on where to start to try improving performance. The current prop is a SS 19? pitch. I have thought of changing props and decreasing Pitch for improved RPM?S but worried overall speed will decrease (according to what I have read). I?m by no means a mechanic although I can handle tools and not afraid to get my hands dirty. Thanks in advance for any suggestions or advice... Jeff
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Any way to question the previous owner regarding WOT RPM's/top speed to find out if anything has changed?....
 
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