300ex Won't Run Right
 

I just bought a '97 300ex it starts fine,but once you start going it loses all power and throttle response. Could it be a carb problem? Or is it electrical my spark is pretty weak and the used plugs are black. What do you guys think?

Thanks

300ex Won't Run Right
 

try a new plug first, the move on to carb

300ex Won't Run Right
 

I tried a new plug today and it didn't help, so I looked at the carb all the jets looked clean and so did the rest of the carb. Does anyone know what the carburetor settings are for it?

300ex Won't Run Right
 

Sounds like you are having a jetting problem. If your plugs are black then u are getting to much gas and not enough air. Your jets might be clean but their might be something wrong with them or other problems like boring the motor 10 to 30 over with fatory jets instead of high performance ones or having a after market muffler with factory jets or even a high performance filter with factory jets. You have two main jets the needle jet and the bottom bowl jet. Try getting a Dyno Stage 1 jet kit follow instructions with the air mixture screw turned til it seals and then a one and a half turn counter clockwise and then see how it goes from there. If you have anymore problems just email me back.

300ex Won't Run Right
 

If you have a carb with a big square plate on top with a round raised center, take out the 4 screws that hold the plate down. Check the rubber diaphram for any holes. If it's not completely intact, replace it. Hope that cures the situation.


JTAK