Stihl FS56 Trimmer - starts with choke engaged and runs full speed in same position

Hi,
Last week my faithful Stihl trimmer started right up with the choke engaged, but when I used the throttle it bogged down and stopped. I went thru this a few times, and it continued to bog when I hit the throttle. After a couple of tries, I realized it would continue to run full speed with the choke engaged. So even though I had no throttle control, I managed to trim the front and back yards.

Afterwards, I replaced the plug, checked the spark arrestor (clean) and visually checked the carb. I did notice gas was leaking and the filter was wet.

I "assume" the carb is the problem, but am wondering if its simply a matter of switching out gaskets/membranes or do I need a new carb, or is it time for a new machine?

Your help and comments would be greatly appreciated!

Thank you!
Mobilman44

Well, couldn't get any help on this problem so I attacked it myself.........

Got a new carb off Amazon ($17) and it took me an hour to pull the old one and install the new one with fuel filter, etc. Best I can tell is the internal diaphragm and gaskets were leaking. Mechanically it all appeared to be just fine.

Got it back together, filled the tank, primed the pump, and it started on the third pull.

Of course the test was using the throttle, and I'll be darned if it didn't work like a charm!

Down here in Texas we call that a real "YeeeeeHaaaaa" moment!

Thank you,

Mobilman44

Seems to be a real common problem these days. Really small passages in these carbs and sometimes looks like the gas itself clogs them up. Good thing is that the carbs are dirt cheap to replace. Usually have welch plugs that seal off passages and you pretty much destroy the carb getting into there.

Just finished cleaning an old Echo blower (PB230LN). (This machine sat for years)..

Would not run, plug either soaked or dry. Cleaned by hand 3 times, no luck.

Cleaned in an Ultra Sonic cleaner (with soap and water). Three treatments on the metal body, two on the plastic throttle.

Re-assembled, runs like new..

So yes, very small crap does get in the system.

Run it dry when done with it un-less your using a very good fuel stabilizer..