Stihl FS-55 Valve Adjustment

[Buckeyeman]

I'm trying to find out if there is a valve adjustment on a Stihl FS-55 trimmer. If so what are the specs. I put a new carburetor on it, use 93 octane no ethanol, and it's hard to start. Fuel pickup and hose were replaced also.
Thanks

 

[oldnslo]

If this a 2-stroke engine I doubt there is any valves to adjust. Might be a reed valve between carb and crankcase.

 

[dodge man]

Some of the newer stuff is 4 stroke. I have no idea how to adjust the valves. Does it have a spark arrestor. I’ve seen those clog up.

 

[RandyT]

Froms the parts diagrams that I found FS-55 is 2 cycle so no valves to adjust.

 

[ericm979]

Clean the muffler screen. Did you adjust the carb? They're not shipped correctly adjusted. Instructions are in the shop manual.

The low speed mixture should be slightly richer than what gets the highest idle. Then use the throttle stop to set the rpm under what starts turning the string drum and fast enough to be even. Then go back to the mixture.

 

[Dan Hunter]

You didn't mention whether you put in a new plug. If not, do so. You'd be shocked at the number of people laboring away with poor running 2-stroke units with a tired plug when it's just the easiest thing in the world to fix. I change out annually now but have spare air filters and swap after extensive use, cleaning the old one at my convenience. I'm not a better person but my life is better...with my tools.

 

[Buckeyeman]

You didn't mention whether you put in a new plug. If not, do so. You'd be shocked at the number of people laboring away with poor running 2-stroke units with a tired plug when it's just the easiest thing in the world to fix. I change out annually now but have spare air filters and swap after extensive use, cleaning the old one at my convenience. I'm not a better person but my life is better...with my tools.

Yes it has a new spark plug. Sorry I forgot to mention that. It also has a new air filter too.

 

[Buckeyeman]

Clean the muffler screen. Did you adjust the carb? They're not shipped correctly adjusted. Instructions are in the shop manual.

The low speed mixture should be slightly richer than what gets the highest idle. Then use the throttle stop to set the rpm under what starts turning the string drum and fast enough to be even. Then go back to the mixture.

Yes, I need to fine tune the carb. I have the screw in type of muffler where it exits the exhaust, and the screen has been removed to prevent clogging.

 

[Buckeyeman]

If this a 2-stroke engine I doubt there is any valves to adjust. Might be a reed valve between carb and crankcase.

Does the reed valve go bad?

 

[oldnslo]

Does the reed valve go bad?

They can but I would first look to verify there are leaks between carb and intake and that there are no other vacuum leaks into the crankcase. Any leaks in crankcase will cause 2 stroke to run lean and be hard starting.

Is plug getting wet when doesn’t start?

Like others have stated also confirm good spark or just replace plug, check to verify exhaust spark arrestor is bot plugged.