Stihl fs400 idle problem (what another one)!

[Flea]

Hi all, and many thanks to the mods for allowing me on to the forum!

My question is this, gotta fs400 that starts first time every time, but will it idle, will it eck as like! So I stripped the carb down, cleaned it, but to be honest though the carb looks brand new! Mesh filter wasn't blocked, diaphragm was in good nick,and there's a new spark plug. Checked the gap of the rotor to pick up coil clearance, aboot 0.2 to 0.5 mm!!!

The problem is though, the machine performs brilliantly at half to full throttle, but the minute you take your finger off the trigger it dies... Any ideas?

Oh, the carb is a zama c1q s94 823a. It's the one with all three carb adjustment screws, high, low, and an idle screw...

Any help greatly appreciated, and thanks in advance

Cheers all Lee 😆

[spudulike]

Hi all, and many thanks to the mods for allowing me on to the forum!

My question is this, gotta fs400 that starts first time every time, but will it idle, will it eck as like! So I stripped the carb down, cleaned it, but to be honest though the carb looks brand new! Mesh filter wasn't blocked, diaphragm was in good nick,and there's a new spark plug. Checked the gap of the rotor to pick up coil clearance, aboot 0.2 to 0.5 mm!!!

The problem is though, the machine performs brilliantly at half to full throttle, but the minute you take your finger off the trigger it dies... Any ideas?

Oh, the carb is a zama c1q s94 823a. It's the one with all three carb adjustment screws, high, low, and an idle screw...

Any help greatly appreciated, and thanks in advance

Cheers all Lee 😆

 

Check the Impulse is clear, the fuel line isn't split, the fuel filter is clean, the tank breather is clear, the manifold isn't split, the carb metering height is correct, the flywheel to coil gap is OK and then check the low speed section of the carb is clean. These issues tend to be fuel related!

[Flea]

Phew! All that to check. Ok I'm gonna give all that a whirl. Cheers spud, will let you know how I get on!

Ta. Cheers Lee