Stihl FS-110 dies....

[khutch]

Stihl FS-110 trimmer starts well, runs fine, then will die at idle usually after it gets pretty warm. Doesn't seem to do it all the time, but plenty often. Keep the throttle open some it will run, let it idle, bam dies quick. Done all the usual, filter, plug, etc. BTW, can you check a bad fuel filter by removing it (just for testing), or is that asking for carb problems or does that alter the fuel flow by removing resistance of the filter?

[echoman8]

There are several things that could cause the "no idle when warm" problem. Again please elaborate on all it is doing and all you have attempted.

But this is the classic symptom of a worn or damaged engine (lower part of cylinder). The lower end of the cylinder must be good to deliver fuel to the combustion chamber. As the piston goes up and down, it creates crankcase pressure and crankcase vacuum. This pressure and vacuum is the mechanism that draws fuel into the motor.

As a motor warms, it expands. If the lower end of the cylinder is worn, then “crankcase vacuum” will be lost. There are several things that could cause the "no idle when warm" problem.

As the motor expands, some of the “combustion chamber pressure” will bypass the ring/s and fill the “crankcase vacuum”. Crankcase vacuum is what draws the fuel and air into the engine. The lower end of the cylinder must be good to deliver fuel to the combustion chamber.

A compression test will not detect this problem. The top end of the engine may be good (good to great compression). But, if the lower end has wear/damage, the motor may run until warm and as the engine expands, it will start starving for fuel. It will fail to idle and will run lean at high speed.

Good luck

de

[cpel2004]

From my personal experience Stihl needs to g oback t the drawing board. The 4mix Tech is to sensitive for my needs and the delay in power just drives me nuts. I must say my FS250 is a world of difference, it starts right up and I have direct power when I pull the trigger.

[SMITHSCAPE]

I have the same problem with both of my 110s and one of them is only a month old. Not sure what the deal is.

[lawnboy dan]

4 mix is a lemon desighn. you hear far more complaints vs praise for it. i bought shindawia c4 instead.