RPM's

FlagetFlaget Posts: 8 Greenhorn
I gradually lost 2000 RPM's (down to 3300) on my 1990 Yamaha Pro V150. I had the following done: Compression check > all cylinders 110. Replaced all plugs. Removed Carbs and had cleaned. Replaced all fuel and flushed fuel lines. Replaced both fuel pumps. Replaced impeller / water pump. Checked throttle whereby all carbs open fully. Use only marine fuel no ethanol. Engine now turns 4700 RPM's. I am still missing 500 to 600 Rpm's. Is there anything else I can do or should I be happy this 24 year old engine running this good. I am original and only owner and this engine has never had any serious problems. Engine has only had Yamaha fluids, and marine fuel in it's lifespan. Thanks in advance for your input. Harold

Replies

  • latitudeajustmentlatitudeajustment Posts: 2,001 Captain
    I was thinking the timing may be off, have you checked that. How about doing a decarb, there could be enough carbon build up causing you to lose some off the top end. Assuming you are using the same prop, nothing different there, that would also affect top end. Maybe your tachometer is off-could be something there, check and clean all connections to be sure. Might as well do the battery connections at the same time. You have covered a lot, maybe try posting on a yamaha engine forum, just a thought, best of luck.
  • FlagetFlaget Posts: 8 Greenhorn
    Your answer is exactly what I wanted to hear, "decarb". I just wanted to hear it from someone else before I did a decarb. Timing is perfect and all connections are clean. Thanks, Harold
  • latitudeajustmentlatitudeajustment Posts: 2,001 Captain
    Yeah, the 2 strokes (I have an Erude 225) definitely need this at least once per year. Break out some engine tuner spray and buy a bunch of sea foam or similar product. I continually add sea foam and even startron along with a carbon guard product to each and every fill up. Hope it works out for you.
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