240 GT lunges when mowing

[joea99]

I also posted this in the general repairs section.
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Got an older (of course) 240 garden tractor with the 3 blade mowing deck and Kawasaki 13 HP engine.

Recently rebuilt the mower deck completely. Both belts are new. Last two time I had it out and mowing, it appears to be "lunging". That is, at any speed, it seems to slow, then speed up. No perceptible change in engine speed. But I am wearing ear protection these days.

At first I though it was just a rear tire that went flat while I was out. Crept back to barn an pumped it up and finished mowing. Not sure if it was still lunging badly then, but certainly a lot less. It is a very bumpy field having hosted a family of burrowing rodent for a couple season. They finally moved on, or succumbed to my doctoring.

This time I pumped up the tire first and it is worse than ever. I do see a bubble in the sidewall of the left tire, but I doubt that has bearing. Except on the money I wasted on an inner tube for that tire. Although, it might still be serviceable anyway.

Back on topic. Am I looking at a bad transaxle here?

 

[Richard001]

So what do you mean when you say "lunges when mowing"? Are you saying that the forward motion of the tractor changes without input from you?

You might want to get one of those Tiny Tachs and put on your engine to make sure that the engine is not surging.

Tractor Data shows that your tractor has a 6-speed gear Transmission. So I would assume that this is a belt drive from the engine to the pulley on the top of the transmission.

So I see several probable causes.
- Drive belt slipping
- Drive pulley on top of the transmission is loose causing it to slip.
- One of your axles have sheared the key in the wheel.

Richard

 

[joea99]

So what do you mean when you say "lunges when mowing"? Are you saying that the forward motion of the tractor changes without input from you?

You might want to get one of those Tiny Tachs and put on your engine to make sure that the engine is not surging.

Tractor Data shows that your tractor has a 6-speed gear Transmission. So I would assume that this is a belt drive from the engine to the pulley on the top of the transmission.

So I see several probable causes.
- Drive belt slipping
- Drive pulley on top of the transmission is loose causing it to slip.
- One of your axles have sheared the key in the wheel.

Richard

Yes, that is what I mean by lunging. At first it seemed more like it was just a very bumpy ride due to the ground being uneven or a flat tire. But it became pronounced enough I could detect changes in forward motion.

It is a 6 speed, but for some reason I had assumed some hydro component. Guess it must be geared only.

The first two suspects I had considered, but I think the pulley is keyed. Maybe not. The rear drive wheel being sheared I had not considered.

 

[Richard001]

I'm sure that the transmission drive pulley was/is keyed, but things happen.

Check the axle keys first as they are the easiest to check. Well I'm wrong on that. After looking at transmissions for sale, I see that the wheel bolts directly to the axle. The axle is is one piece and does not have a keyed hub.

Checking the dive pulley will most likely require removal of the transmission from the tractor.