Stihl FS 350 Brush Cutter - Running Problems

[Florek27]

Hello Everyone,

Thanks for allowing me to join.

Question: I have a Stihl FS350 Brush Cutter. I start the engine just fine, but when the engine warms up while using it boggs out. I have to continually engage the throttle while using, once it goes to idle it stops.

After it stops, it can't be restarted until it cools down for about 2 hours.

I've tested spark prior to initial startup and after it warmed (when it wouldn't start again). Both times it has good spark when grounding the spark plug to the engine.

Things I've these done, without any success:

1) Cleaned the spark arrestor (not bad shape)
2) Changed the fuel filter (which was good)
3) Changed the spark plug (old was seemed ok)
4) Changed the air filter.
5) Tightened carburetor nuts to prevent any air leaks. Everything looks good.
6) played with the High & Low Speed Screw according to specifications.
7) Played with the idle adjusting screw, no luck. It should be mentioned that when started the blade rotates at idle no matter how much I adjust the idle screw. Hard to keep it running from more than a couple of seconds when in idle....it dies.

Can it be the coil? While the engine is cold I use an ohm meter at 20K and when I put the positive on the spark plug receiver and the metal bar that bolts the coil on the engine, it reads 1.47 ohms.

Any suggestions?

Cheers,

Florek27

 

[Florek27]

Hello Everyone,

I guess there was 99 views and no replies. So this is what I did, apart from what I did above.

1) I changed the coil, and that wasn't the problem. As mentioned, I saw spark when engine was hot and cold. Some say when it heats up the coil doesn't operate appropriately, but that was not the cause.

2) Changed the whole carburetor. I got a kit on Amazon that replaces all these parts for $40. I think I would try and source a Stihl dealer, but that proved difficult since there are none in the area and their website is not helpful to order parts. So I think they are their own worst enemy. Their kit would be better, because there were some minor differences in the connections that I had to correct, which was a pain.

Once Carburetor was changed everything operated good. However, I can't get the unit to stop spinning at low idle. The blade keeps turning. I just have to be careful. I made some adjustments to the low and high speed screws as indicated in owners manual and the idle screw.

Cheers,

John

 

[Deeres]

Set your low idle carburetor up or down (likely down) to lower idle RPMs to stop the cutter from spinning. My JD-branded 2-cycle unit did the same thing - had to adjust idle down.