G4200 Garden Tractor Mower Deck Vibration

[rreineri]

I purchased a G4200 about a month ago, and am finally getting around to wrenching on it to put it in top shape. Typical issues that happen over the years, safety switches bypassed, small fuel leak, needs all filters and fluids changed, etc.

Now, I've never owned a diesel tractor before, let alone one this heavy and solidly built so I have no reference to go back on.

There seems to be a bit (not a lot, but certainly more than any riding mower I've ever been on) of vibration when the mower is engaged. Not sure if on this heavy of a machine it is normal. The blades spin freely and smoothly, bearings seem OK (shafts not loose, wobbly or binding).

Any ideas on what to check? Could the blades be "unbalanced" ? Is this just normal?

Also, one other thing. When I pull the fuel shutoff switch, the engine stops immediately, but so violently I was thinking it was going to jump off the motor mounts. If I didn't know better, I'd say it felt like someone shoved a crowbar into the flywheel. Is this normal for a diesel?

I've ordered the service manual from Messicks, but it won't be here for a week, and weatherman is calling for a few nice days in a row. Would like to wrench on the orange beast a bit!

Robert

P.S. This thing is POWERFUL. I ran it right through a big mess of wet leaves and it didn't even slow down or labor. Amazing how much torque a diesel has compared to gas engines.

 

[Dave_eng]

I purchased a G4200 about a month ago, and am finally getting around to wrenching on it to put it in top shape. Typical issues that happen over the years, safety switches bypassed, small fuel leak, needs all filters and fluids changed, etc.

Now, I've never owned a diesel tractor before, let alone one this heavy and solidly built so I have no reference to go back on.

There seems to be a bit (not a lot, but certainly more than any riding mower I've ever been on) of vibration when the mower is engaged. Not sure if on this heavy of a machine it is normal. The blades spin freely and smoothly, bearings seem OK (shafts not loose, wobbly or binding).

Any ideas on what to check? Could the blades be "unbalanced" ? Is this just normal?

Also, one other thing. When I pull the fuel shutoff switch, the engine stops immediately, but so violently I was thinking it was going to jump off the motor mounts. If I didn't know better, I'd say it felt like someone shoved a crowbar into the flywheel. Is this normal for a diesel?

I've ordered the service manual from Messicks, but it won't be here for a week, and weatherman is calling for a few nice days in a row. Would like to wrench on the orange beast a bit!

Robert

P.S. This thing is POWERFUL. I ran it right through a big mess of wet leaves and it didn't even slow down or labor. Amazing how much torque a diesel has compared to gas engines.

First, free Operator's manual on Kubotabooks.com.

When chasing down mower deck vibrations, my first suggestion is to remove the blades and see if the vibration disappears. Bent blades and worn blades are common.

Next, worn belts can cause vibrations. A belt can wear heavily in one or two spots and it will operate like a car tire with a flat spot.

Remove the deck belt and make certain each spindle assembly turns smoothly and has minimal play in all directions. The belt must be removed.

Make certain the tensioner pulley on the deck operates smoothly and without a lot of wear on its pivot.

Deck pulleys can be bent. A careful examination should reveal this. The groove on the pulley will have some spots wider than the rest of the pulley's groove and the belt running on this pulley will produce rough operation.

Belts are available from non Kubota sources. Having a one piece belt (unbroken) to start with makes matters much easier.

On youtube there are videos showing you how to determine the belts length and width.

https://www.youtube.com/watch?v=2kYLYrw0gUE&t=22s

If you take these measurements and come back, I will show you how to order a top quality Kevlar belt.

If there is a shaft drive from the engine to the deck, carefully check U joints for both slop and stiffness. It might be best to remove this shaft to thoroughly check it.

Dave

 

[rreineri]

First, free Operator's manual on Kubotabooks.com.

When chasing down mower deck vibrations, my first suggestion is to remove the blades and see if the vibration disappears. Bent blades and worn blades are common.

Next, worn belts can cause vibrations. A belt can wear heavily in one or two spots and it will operate like a car tire with a flat spot.

Remove the deck belt and make certain each spindle assembly turns smoothly and has minimal play in all directions. The belt must be removed.

Make certain the tensioner pulley on the deck operates smoothly and without a lot of wear on its pivot.

Deck pulleys can be bent. A careful examination should reveal this. The groove on the pulley will have some spots wider than the rest of the pulley's groove and the belt running on this pulley will produce rough operation.

Belts are available from non Kubota sources. Having a one piece belt (unbroken) to start with makes matters much easier.

On youtube there are videos showing you how to determine the belts length and width.

https://www.youtube.com/watch?v=2kYLYrw0gUE&t=22s

If you take these measurements and come back, I will show you how to order a top quality Kevlar belt.

If there is a shaft drive from the engine to the deck, carefully check U joints for both slop and stiffness. It might be best to remove this shaft to thoroughly check it.

Dave

Thanks Dave! Great pointers. I'll be starting on it in the morning using all of the above suggestions.

 

[grinchsr]

I own a G5200 and am new to the diesel world but if this helps mine also shuts down the same way. I think it is due to the amount of compression a diesel produces.

 

[SidecarFlip]

Going to put my money on a worn driveshaft.

 

[D2Cat]

I agree with Grinchsr, that's the way a diesel functions and the OP is not use to the commotion!

Go through the belt and blade checks Dave listed and you'll be fine.

 

[dlundblad]

I have 2 G5200s. Both turn off rather rough.

I would definitely try the blades before you go digging too far. One sad thing with these is that their parts are getting harder to find.. Hence why I have 2.