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tmlawr
08-22-2005, 10:20 AM
Have a 1996 350 yamaha big bear.

Only modification is a Cobra Pipe.

Installed a new standard carb kit and new std spark plug

Machine ran excellent for 1 hour or so, ran it at medium to high speeds.

Than ran machine for 1/2 hour or so a low speeds, plug fouled and performance dwindled!!!

Tried leaning needle jet, performance was poor.

Tried a hotter plug, ran even worce!

Any suggestion would be greatly appreciated, my patients are running thin!!!

Machine will idle well, a little hard to start (needs choke) after new carb kit.

If I adjust pilot jet, that only leans or riches out the idle to 1/8 throtle?

I assume the pipe makes the machine run leaner, puzzled why plug carbon fouls?