Pulsating throttle

truckerlary · Sep 15, 2012

I have farmall 400 that I just installed a 281 in place of the 264 that came with the tractor. When I start the engine it wants to pulsate from idle thru about half throttle. If I pull the choke out it smooths out and runs right. I have sprayed penetrating oil around the manifold and carb to see if I had a suction leak but didn"t find anything. I adjusted the pivot on the governor but that didn"t help either. The governor was originally on the 264 and worked good. The carb and manifold came with the 281. From half throttle on up it seems to run okay. Anyone have any ideas? Thanks Larry

rustyfarmall · Sep 15, 2012

(quoted from post at 11:53:22 09/15/12) I have farmall 400 that I just installed a 281 in place of the 264 that came with the tractor. When I start the engine it wants to pulsate from idle thru about half throttle. If I pull the choke out it smooths out and runs right. I have sprayed penetrating oil around the manifold and carb to see if I had a suction leak but didn"t find anything. I adjusted the pivot on the governor but that didn"t help either. The governor was originally on the 264 and worked good. The carb and manifold came with the 281. From half throttle on up it seems to run okay. Anyone have any ideas? Thanks Larry

It's a shot in the dark, but possibly the idle circuit in the carburetor needs a good cleaning. Possibly the carburetor just needs adjusting.

old · Sep 15, 2012

If it is running lean it will do just that. So either adjust the main or idle jet or the carb needs to be cleaned

truckerlary · Sep 15, 2012

Thanks guys. I did notice that when I screwed the
low speed adjustment in it was somewhat better, but
only when it was screwed all the way in. High speed
adjustment has no noticeable change when screwing it
in or out. I guess I need to get a carb kit.

rustyfarmall · Sep 16, 2012

(quoted from post at 15:12:33 09/15/12) Thanks guys. I did notice that when I screwed the
low speed adjustment in it was somewhat better, but
only when it was screwed all the way in. High speed
adjustment has no noticeable change when screwing it
in or out. I guess I need to get a carb kit.

That high speed adjustment WON'T have much effect UNLESS the engine is running wide open under a full load. Just turn it in gently until it bottoms out, then turn it out a full 3 turns and leave it there.

If the air/idle mix screw has very little effect, that carburetor needs a thorough cleaning.

Pulsating throttle

truckerlary

Member

rustyfarmall

Well-known Member

old

Well-known Member

truckerlary

Member

rustyfarmall

Well-known Member

Similar threads