1991 yamaha 225 surging at 2500-3000 rpms

[jc09]

I have a 1991 yamaha 225hp - it is in good shape - however it surges after running awhile at 2500to 3000rpms. Where should i start? Ihad the carb rebuilt 2yrs ago,but i also haven't used it for 2yrs. It sounds good while running, no hesitation or drop in power.

 

[cousinabe]

Re: 1991 yamaha 225 surging at 2500-3000 rpms

surging after running a while could indicate a fuel restriction.
could be related to faulty fuel pumps, clogged filters or tank vent issues.

Does pumping the primer ball help?
Does running with the gas cap off help?

T in a vacuum gauge between the lp fuel pump and the engine filter. should be between 1-4Hg. anything more indicates a restriction from that point to the tank, less indicates a bad fuel pump or air leak in the line.