2001 Yamaha 115 2-stroke drops in power at WOT

[MusicManJP]

I had a major problem getting my 115 Yamaha 2 stroke to idle correctly (too little running for the last two years). With much cleaning and running at dock it now idles smoothly and I thought I was good to go. Took it for a test run and as I reached about 3/4 throttle, instead of accelerating, it actually slowed down. The speed at which it started slowing was probably 9 or 10 mph below it's normal top end speed.

 

[jeffersondodson561]

Re: 2001 Yamaha 115 2-stroke drops in power at WOT

Cleaning? Total carb overhaul? Did you do a sync and link on the carbs and verify that the throttle plates are opening vertical at wide open throttle.

 

[99yam40]

Re: 2001 Yamaha 115 2-stroke drops in power at WOT

Make sure the fuel supply is in good shape.
Could be pump not furnishing enough, sucking air, or restriction

 

[MusicManJP]

Re: 2001 Yamaha 115 2-stroke drops in power at WOT

I didn't rebuild the carbs, just used deep creep and sea foam to clean them. It now idles fine (the original problem). I think I may have adjusted the pilot screws in an attempt to fix the idle problem. Once that was fixed and I discovered my NEW problem, I reset them to the 5/8 recommended by the manual. Everything still as before....good idle, loss of power at the top end of the throttle. I am currently operating from a portable tank that I believe to be functioning properly.