Engine dies with throttle?

I know that this question doesn't belong in the "Cars & Transportation", but since many here are mechanically inclined, I thought I'd post the question here.

I have a weed eater, 2 stroke. It starts just fine, and it idles perfect at half choke and at no choke. But at either choke, if I give it any throttle, it dies. If I move the choke between the half and full (I geuss that would be 3/4 choke) it does run, but at reduced power, and excessive smoke.

The spark plug is new, gas has proper gas/oil mix, engine is definately warmed up as it's been running for about half hour give or take, what am I missing? 3/4 choke doesn't let the engine run as it should and sometimes it pops out of 3/4 as the dedent spring sets it at full and at half choke.

2016-04-13T14:06:26Z

By the way, I'm pretty sure that a clogged air filter is not the cause because I'm also trying to run it with no filter. Still no difference.

paul h2016-04-13T14:42:13Z

Favorite Answer

Sounds like the high speed mixture screw is possibly set too far open...CCW....causing the engine to run too rich and smoke or die. You'd need to have repair shop/dealer try adjusting the mixture screws for proper idle and high speed operation or try it yourself if you feel up to it. The engine/ carb plastic shrouding usually has a couple holes near the carb location where you can insert a screw driver to adjust the mixture screws on the carb...one screw is for low speed/idle mixture and one is for high speed in most cases. High speed may be marked H and low is marked L on the shroud cover in some cases. Locate the high speed screw and turn it clockwise an 1/8 turn which will lean the high speed fuel mixture ...less fuel flow......then try starting/warmup and then throttle up and see if it runs better...if not ...try another 1/8 turn. Work in 1/8 turn increments at a time until engine does not bog or smoke....let engine run for a few minutes between setting changes...no more than 1 full turn of adjusting.

The usual way to adjust high speed mixture is to warmup engine and open choke and throttle up all the way...then adjust high speed screw to get highest rpm's that engine is specified for by the maker...usually around 3200-3500 rpm's for small engines...which may need a shop with proper tools to gauge accurately. If speed is set too high, it can burn out the engine prematurely from running too lean....set too low and it can run too rich, foul the spark plug earlier or stall under load.



Info on adjusting...
https://www.google.com/#q=weed+eater%2C+2+stroke+adjust+high+speed+mixture+