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Willy91

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I'm wondering if anybody here has any expeirience with nitro powered rc monster trucks. I have a CEN fun facter monster truck and I'm needing some help adjusting the carb. When I go from idle to full throttle it has a very bad stumble to it, and then it takes off. From what I understand it has something to do with the adjustment srews on the carb. but i'm not sure what to do with them. any help is apprieciated Thanks......Willy
 
When you say stumble, do you mean it gurgles or does it just flame out? If it gurgles, your low speed needle needs to be turned clockwise about an 8th of a turn to lean it out. Keep leaning it until it jumps off the line but does not flame out.

If it just flames out, do the opposite (turn it counterclockwise).

All of this, of course, is assuming you've tuned the high speed needle in, get good smoke when at full throttle and your engine temp's aren't higher than 230 or so. Should always tune the high speed needle first, then the low speed needle.

Good luck!
 
MW has a good starting point. Also take in consideration on the weather. Is it cold, hot, humid,what? Let us know.
 
stumble I mean it gurgles or boggs down when I first go to full throttle from idle and then it smooths out. I have the big screw(don't know exactly whats it's called) adjusted so that it is running at the right temp and is giving a good stream of smoke at full throttle, but off idle it spits raw full/tons of smoke out of it. right now it's 70 degrees but it did it this winter when it was 20 degrees to.
 
You might have the high side too rich along with a low-side that is too lean. Go back to the factory settings and try again.
 
it's all at factory settings beside the the large air fuel mixture screw wich is leaned down from factory to where it needs to be.
 
Do you have a camera that is good enough to take a couple pics of the engine? Maybe if we see the engine/carb we can help you out. Some engines are single needle, some are 2 needle, some are 3 needle... The more needles, the more complicated. 2 needle carbs work best for most people.
 
Once you have it running and up to temp, drive it toward you, pinch the fuel line a inch or so from the carb and see how long it takes to stall and die. 3-4 seconds and the LSN is probably ok. 4+, it's too rich. <3, it's too lean.
 

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