Re: 25horse johnson wont run wide open
If you are getting full flow to the carb:
High speed passages in carb are blocked/restricted. Might be partial blockage from junk in carb.
Try your same test with a squirt bottle of pre-mix. if a light mist into the carbs boost power, you are starving the motor. see above.
Only other thing might be timing to far advanced. Kind of not likely on this setup. Parts wear normally= timing retarded.
