FS 400 stops

cherami

Member
I have this strimmer which has had a replacement carburetor, ignition coil, piston ring, new fuel lines and repaired wiring near the junction with the motor. It starts but then after a short while it stops and will not start again. The next day it starts again but as I said does not stay running. Any clues please.
 
Hello C.,

Are you using the proper fuel/oil mix? I don't recommend store bought Tru-Fuel, that stuff has created more headaches than anything.

Verify you are not losing spark if it is an aftermarket coil. Only use Stihl brand ignition coils.

The correct spark plug number is also very important also but avoid Amazon for any parts.
 
Look at this first. Soft copper wires with probably a crimp connection joint = a recipe for disaster. All the engine vibes will kill a poorly terminated butt connection. Check continuity here.
Yes will look at that again, think I could also do with another handle for the throttle and switch, getting pretty old.
 
Hello C.,

Are you using the proper fuel/oil mix? I don't recommend store bought Tru-Fuel, that stuff has created more headaches than anything.

Verify you are not losing spark if it is an aftermarket coil. Only use Stihl brand ignition coils.

The correct spark plug number is also very important also but avoid Amazon for any parts.
Use 95 lead free and stihl oil mix at 50 to 1.
The price of Stihl ignition coil here in France range between 130.00 to 180.00 euros very expensive and one can never be sure they are genuine.
Has original number spark plug. I use the green spark web for most electrical.
 
I have this strimmer which has had a replacement carburetor, ignition coil, piston ring, new fuel lines and repaired wiring near the junction with the motor. It starts but then after a short while it stops and will not start again. The next day it starts again but as I said does not stay running. Any clues please.
Clean and replace the OEM Zama carburetor with the aftermarket one you probably put on. Do not spend any more money for parts on this trimmer.
 
Hello C.,

Check the piercing spring at the end of the coil wire, it attaches to the plug that is covered by the boot. I have seen then wear loose in the end of the coil wire and cause problems like this. Some had this faulty design, and some did not.
 
Clean and replace the OEM Zama carburetor with the aftermarket one you probably put on. Do not spend any more money for parts on this trimmer.
New aftermarket carb original much too expensive here in France. It is an old strimmer but it cost me 1000 euros so dont really want to get rid of it.
 
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