2001 Yamaha 115 v4 2 stroke no mid-range

todd duncan

Hopefully some help, it idles great, fires right up, when accelerating to get on plane pulls fairly good at first, then hits a wall where it really struggles to accelerate, once above 3000rpm? (Guessing, no gauge) it takes off like a rocket.

chaser48

carbs may need cleaning

todd duncan

is there a timing advancer on this motor? 

rehartline

Had the same issue, it was a carb cleaning issue. Didn’t seem to make sense the way it ran and I had to find a guy that new how to do it right but it’s been fine ever since. I learned to get picky about my fuel (ethanol free) and filter/water separator (Racor). 

lemaymiami

One other consideration.. if that old motor is on an older boat - particularly if it's had ethanol in it - a complete cleaning of that fuel tank before going to rec90 (ethanol free gas...) as well as thorough inspection of your fuel lines, filter, any junctions, etc.  might also be in order... 

cortr

Ethanol is bad stuff, whether new or old boat. Try to avoid it if possible!

lemaymiami

If you run ethanol (and nothing else) and are the kind of user that no gas in the tank ever goes unused more than a week or so... you can get good service with ethanol... Me, I've run nothing but cheap ethanol laced gasoline for years - through multiple motors - and never had a problem - but once again I'm on the water a heck of a lot more than any weekend warrior... Most anglers will struggle to clock 100 hours in a year on their motor... I'll do that in one month - every April (excepting the pandemic years when all my customers disappeared on me...).  

The reason I've done well is that I've been running Evinrude E-Tecs (90 hp) since 2005 - and they're just not fuel sensitive at all... Now that BRP has quit making them my next motor will have to be a four stroke, no other choice...  When that happens I'll seriously consider making the change over to straight gasoline - but I'm not looking forward to it at all....  since it will boost my fuel costs and it's just not convenient when you're running day after day and there's not that many stations pumping Rec 90 fuel...