FS-250 problems

[Nonprophet]

It's been running great--no issues. Haven't run it in 4-6 weeks. I only run clear high-octane fuel and synthetic oil mix. Yesterday, it started running poorly after 15 mins of so of use--idling rough, and having to feather the throttle to get it up to full speed which it would eventually do, then it would bog easily in heavy stuff.

I drained the old fuel and added fresh. I changed the spark plug. I cleaned the air filter. I took the carb out, cleaned it, and re-installed.

Now, it starts just fine, but will not throttle up at all--it just bogs. I adjusted throttle cable on the bicycle handlebars, it's tight. I checked fuel lines for cracks, I don't see any and fuel filter is pretty new.

Any suggestions on what the problem could be?

Many thanks!

 

[jughead500]

ok how old is it?clear high octane?ethanol?
check the spark sceen in the muffler,check the fuel filter.

 

[Nonprophet]

The machine is 4 years old, light residential use only. Never had a single problem with it. The fuel is what we call "clear premium" high octane (93+) no ethanol. Spark screen is clear, I'll replace fuel filter.

 

[sawfun]

Check fuel lines and did you install a new filter? High octane fuel is not necessary but non-ethanol fuel really is. The pump gas, even the high octane type, for cars has ethanol in it which harms fuel lines and carb diaphrams, even thought the diaphrams look good with no pin holes. I would pull the muffler and check the piston condition just to be sure of condition.

The Zama carb on my fs 250 leaves a lot to be desired. Mine does not idle well or return to a good idle consistantly. I have rebuilt it with a new Stihl kit and had a dealer (where i purhased it new) try to fix it. The machine will not run upside down at all when edging. Time for a new carb on mine.

 

[Nonprophet]

It was the spark arrestor screen! Thanks everyone! I thought I had checked it, but I had not. It was badly plugged up.....

 

[atpchas]

When you say you cleaned the carb, did you clean just the exterior or did you open it up and check the innards? I had a similar problem with my FS-250 a while back and it was a clogged screen inside the carb. I was so relieved, I was expecting something more serious and expensive. Hope you're as fortunate.

 

[jughead500]

just for everyones information.i ordered a chinese carb from ebay for a friends fs120 and it worked very well.
both fs250's i have has had carb trouble..

 

[1Alpha1]

Lose the spark arrestor screen. No more problems.

I have an FS-250R. The screen was the 1st thing to go bye bye.

 

[lone wolf]

The carb may or may not be the issue. I have had some of these with bad coils that act like a bad carb. Best thing to do is swap the carb with a runner or buy another if that dont help its the coil.

 

[sawfun]

Thanks for the input everyone.