motor or carb problem????

[tsargent4]

i am having a problem that happens something like this---i blip the throttle and it's like the motor is trying to catch up with itself and is reving high and then as a few seconds go by it will finally ease down slowly on the high rev...what would cause that? is something in the carb stuck?

[daddio]

Have you cleaned your carb with the Automotive spray type carb cleaner?

[tsargent4]

nope

[daddio]

How old is the carb?
Has it ever been cleaned? Never use carb cleaner on the slide.
Did you add or change anything since it was running right? Pipe, filter, intake, fuel, etc.
Did it ever run correct?
What jets and needle are you running?

[tsargent4]

its an 06 carb and motor....i have a 170 main, 42 pilot (probably needs a 45)...stock needle on 3rd clip from top, and Moose Racing air fuel screw...has full Bub Moto C-4 exhaust...stock motor... and Uni air filter...93 octane....never been cleaned...or used anything on the slide...

[jgxcracer]

You need to bump your main up to around a 180 to 185 and if you have you air box lid off you are going to need to go up on your pilot jet. It sounds more like you are lean on the bottom, pilot, but these carbs are tricky sometimes. Also, try backing your idle set screw off as much as you can but still keeping the idle close to where you want it. You would be surprised how much that adjustment will hold your idle high when you let off the throttle when it has just a little pressure on the throttle plate.

[Fast350ex]

Definitely a lil' lean. Remove the pilot; find one of those trash bag twist ties; burn the paper off of it until its a very thin wire and shove it through the pilot and work it back and forth using carb cleaner. Then blow it out with some air. lol.

If this doesn't fix the problem you most likely need a valve adjustment.