Poor idle

bob6940 · Jan 20, 2017

My 41 John Deere B is surging when its idling, actually it sounds like it's surging all the time its just more obvious when its idling.Its my first John Deere guy's so I'm struggling a bit to figure it out.Any help would really be appreciated.Seems to run real well other than that.

RandyB(MI) · Jan 20, 2017

Open the idle needle 2 turns. That's the adjuster on top and on the flywheel side of carb. Open throttle 3/4 - wide open (while running) and slwly close the load needle , the one on top of carb on clutch side. If tractor stops or spits pops or anything, your carb need rebuilt. Other things can cause surging but it's usually plugged idle circuit or sloppy throttle shaft /bushings. This causes the tractor to suck little gulps of fuel from load nozzle and then governor has to try to control this uneven gulping of fuel and rpm which causes the surging. Could be binding linkage also but the carb test needs done too.

Mike M · Jan 20, 2017

Well since it is your first. Not to be mean but they call them poppin johnnies for a reason. It might just be "normal" ? Had a guy drive me nuts on his A carb. said it would not run right. I finally went to his place and fine tuned it. All seemed well to me. Then he said well my JD 60 doesn't do this. Well of coarse not, JD designed it with a 2 bbl. carb. for a reason.
So I am always skeptical of rough running complaints.

buickanddeere · Jan 21, 2017

A large displacement, low rpm twin engine with a single barrel carb by design will not have even air/fuel distribution cylinder to cylinder. Tis the nature of the beast.

susandiane · Jan 21, 2017

Worn throttle shaft leaking air can cause it to "hunt",as will intake manifold or carb to manifold leak. Spray some carb cleaner in these locations and see if it causes any change. Good luck!

David G · Jan 21, 2017

I would suspect a lean condition or sloppy governor issue.

I do agree with B&D on the single body throttle not being optimum, it should be better than that. All engines that share intake runners suffer from this, even "100" cylinder engines, but more cylinders average out the disturbances. The cross flow heads on the new engines totally eliminate these issues and match flow much better. Timed fuel injection can help somewhat, but never get it perfect.

bob6940 · Jan 22, 2017

Thankyou very much for the tips and advice.Some of the linkage is really gummed up, later in the week I'll try some of the other suggestions.This is my first Deere, but not my first tractor and I've come to know when something doesn't sound right it probably isn't. The best place to get good advice is always from someone who's done it.

Poor idle

bob6940

Member

RandyB(MI)

Well-known Member

Mike M

Well-known Member

buickanddeere

Well-known Member

susandiane

Member

David G

Well-known Member

bob6940

Member

Similar threads