SF111R not starting

ueww40

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When squirting a few drops of fuel into the carb it will start but dies as soon as the squirted fuel is used up. Primer bulb is filled up with fuel. Fuel filter in tank has been replaced. It ran a few days ago. Stihl dealer says trimmer is not worth fixing, it has no compression which is probably BS. I replaced the carburetor and messed with the H and L needles. Exhaust is unrestricted. If compression was the problem I guess it wouldn't start when squirting fuel into carb. Any ideas??? Btw, does this engine have compression release to make starting easier?
 

ILENGINE

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My concern at the beginning is what is the compression reading. Above 90 then I would consider replacing the carb and see what happens.
 

StarTech

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4180 4 mix engine.

Yes it has a decompression setup so the valves needs adjusting every so often. Now does a special feeler gauge as most are too wide to use.

I personally use a different minimum compression number of at least 100 psi.

Also the lat time I brought it was around $50 and but now you can get a repair kit for thru Amazon under RB-287. CTS has two kits for under $10 including shipping. It is mostly a stiffen metering diaphragm not allowing the metering needle to open up.

I just added those to my next purchase from Amazon myself.
 

ueww40

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I just picked up my trimmer from the dealer and I had a long talk with the service tech who worked on it. He said he did a compression test and a leak down test and the leak down test failed miserably. He said that the compression loss is caused by a faulty exhaust valve. Now I feel newly encouraged and my nest move will be to remove the head and take a good look at the valves, valve seats, cam, push rods etc. Updates will follow.
 

ueww40

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Thanks StarTech for the decompression info. How does it work on that engine?
 

StarTech

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It opens one slight right before TDC compression stroke. As for which one I haven't paid attention but I think it would be the intake valve.

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ueww40

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Thanks StarTech. I couldn't have asked for a better explanation. Before I tear into that engine I will check and make sure that the decompression nipple moves freely and is not stuck
 
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