stihl fs 400 cant get to idle

[Maico490]

Thanks for that Spud. Must admit the problem had me at my wits end and took ages to work out. As there was little information on it anywhere, other than "Buy a new carb" I did the post. Although like you I've been playing with small engines for years these little probs still come along to catch you out. The Zama website is well worth a look even for old hands.

The Maico was a German MX bike. 490cc piston ported with no trickery at all but put 50 horses to the back wheel when the Japs struggled to get much over 40 with pipes, wires and gizmos everywhere. I took MX up again for a few years and on a long start it certainly made the youngsters on their "powerfull" 4-strokes a shock. Only thing was they soon got by again on the rough stuff. The one thing I really kick myself for selling.

[spudulike]

Thats one big two stroke - back in the 80s, one of the guys in the factory where I worked brought in a Honda Red Rocket - man that thing went - couldn't catch up with him on my tuned 400/4 - they were the days:thumbup:

[Mesterh]

I had the same running prob with an old still blower.

 

Bought a very cheap ultrasonic cleaner, bunged the stripped down carb in, back together and worked great.

 

That was after I had tried all kinds of carb cleaners which didn't work.

[ScotClayShooter]

When my FS450 was playing up like that it was the cylinder bolts had come slack! Just caught it in time.

might be worth doing a pressure/vac test on the the engine.

[badger22]

Hi Spud.

My 450 stopped the other day the smaller of the Welch plugs(ali plugs) has fallen out so nothing to lose Superglued it in.

Fuel primer has filled up and machine seems to be running O.K

I know this should not be done as could end up with glue in the jets as well as all over my fingers.

Will see how long it holds up for. Will the fuel effect the glue

If or when it fails were is the best place to get a new carb.

Just wanted to know if this was the only fault.

Could not have done this without you and the others info on this thread.

Many thanks.

P.S Do you know the name of the Welsh chap who puts these in and were he lives.