300ex can't throttle out ( governs in waves )

[squarejsj]

My 1996 300ex will not throttle out and stay open. It acts like a governor is constantly cutting off the fuel supply.

I tried a new cdi box ( stage 3 ) but no joy, same problem.

The carb is clean, new rings, fires right up, will idle after it warms up. New gas tank, and the lines are all clear and it seems like fuel will flow freely when I turn the pet-cock on ..

I just can't get the thing to stay open.

Any ideas ??

Many Thanks for your comments and time.

If we need to get really fancy, I can take some film of it and post it as a .wav file or something ...

[tayyo789]

try checking out your float bowl if you havent already. and maybe your intake boot. i had a quad that did that and the intake boot was cracked.

[mikey726]

My 300 did that and there was something that held the reverse arm down that was bent. It was a long time ago so I don't remember exactly but if your reverse light flashes a little when it happens, that's your problem. Before I got it fixed I wrapped a rubber band around the starter motor cover to hold the lever down.

[deathman53]

I was gonna say something about the reverse or the wires to the parking brake are touching. I had that problem on my yamaha warrior, it was the parking brake wires.

[Sjorge450R]

check the two wires on teh right side of the motor. The ones that go into the clutch cover. They are the ones that change the rev limiter for reverse and drive so just make sure both are properly plugged in. Let us know what you find out.