70hp Yamaha Carb help

[windknotnc]

Bought a used 1995 yamaha 70 motor cranks up fine and seems to idle well when cold. Runs WOT great at 4900-5500 rpm. When I back of to about 3500 it boggs down and surges some then goes to idle, but idles rough. If I go to neutral and then to WOT it takes off fine, but if I go slowly it boggs down at about 2500. I have new gas, fuel water separator, put some ring free in the gas, and ran a can of Deep Creep through it yesterday afternoon. The ball is tight and it does not seem to have a fuel pump problem. My guess is low speed jets on the carbs. Anyone with other thoughts or ideas. I have read I can clean these without taking the carbs off. Is this so? If not I will be hauling to the shot for carb rebuild.

 

[WillyBWright]

Re: 70hp Yamaha Carb help

You can't really clean them without disassembly. In a 4-stroke you can add things to the gas to dissolve small amounts of varnish, but many of those additives mess with 2-stroke oil and are not recommended. Check the label before using any additives in a 2-stroke. It has to specifically say that it's safe for 2-strokes.