Repairs 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving

bruceha2000

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  • / 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving
Got this free (best price) from a friend. Rust is fine if it is FREE rust ;)
- Left rear tire wasn't holding air so I put a tube in it. I can't for my life get the wheel off the drive shaft, PB Blasted it several times, that thing is just not coming off. Might have to get a wheel puller. Slimed the front tires since the sidewalls look worn and they have been plugged at least once each.

Figured I was good, was out mowing last week (3/4 acre). All was well until I was ~95% done. Then it started to sound odd (hard to tell just what with the muffs on) for a couple of minutes, then normal again. But I was only mowing with 1 blade. Figured to finish that way since I was almost done and then find out what was wrong on the weekend when I had time ... until I came upon a black plastic pulley in 2 pieces. Stopped mowing then! I drove it back to the barn and left it for Friday night. I took the deck off and found the backside idler pulley had seized and the belt ripped right through it. The belt itself was still in fine shape. So I get a new, metal this time, pulley yesterday and put it on. Things look good. Until -

I started the tractor and it just does not want to move faster than a VERY SLOW crawl both forward and reverse. If I push the lever much past "just in gear" it slows down to not moving. Mind you, it drove back to the barn normally after the pulley ripped apart and sat there for 4 days until I had time to look at the deck. This makes no sense to me, I only messed with the deck.

Research suggests I may need to bleed the transmission or change the fluid. But the question is "How can it be moving fine one day and JUST BARELY the next???" Shouldn't there be some degradation rather than instantaneous? Or are there other possibilities besides purge/change fluid? But still the same question: "How could it happen while the machine just sat for 4 days?

Thanks,
Bruce
 

Rivets

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  • / 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving
I suspect the drive belt first. Make sure that it is in good condition. Also, check the idler pulley, it may have froze up after recent use.
 

Rivets

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  • / 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving
Forgot to say that the drive belt should be tight.
 

bruceha2000

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  • / 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving
Forgot to say that the drive belt should be tight.

You were right on Rivets, thanks.

The belt is fine but was loose. The idler pully bracket was stuck with the spring fully extended. Not sure why they designed somthing that important to pivot on only a washer on "used to be but is now rusty and flaking off" painted metal. I took it apart, PB blasted everything and now it pivots well and the tractor again moves normally.

But, while I had my head up under the tractor, I noticed the plastic fan on top of the transmission was all beat up. One blade is missing, several are oddly shaped.

The question: Is that fan a press on or part of the metal pulley? Please say it is a press on or that is going to be one expensive plastic fan! :)

Oh, and one more question. Is Blaster good enough to lube the bearings in the pulleys or should I be putting something else in there? Obviously can't be too thick since the bearings aren't even visible.

Bruce
 

Rivets

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  • / 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving
No, PB is not a lubricant, use oil. I use left over motor oil, not used, works fine. The fan is for cooling the hydro and needs to be clean and in good shape. Can not tell you how it is held on, because I don't have your model numbers. Lots of different hydros out there.
 

bruceha2000

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  • / 1994? 20 HP Kohler, 50" deck Yard-man Hydro barely moving
The fan is for cooling the hydro and needs to be clean and in good shape. Can not tell you how it is held on, because I don't have your model numbers. Lots of different hydros out there.

For anyone later hunting parts for this tractor, I found Sears Parts Direct has a whole tractor parts list with diagrams.
According to the diagram, the fan is held on to the pulley with a screw. YEA! It looks like the fan hub sits over the bolt on top of the pulley and the screw goes into the pulley body, slightly off center.

The fan is PN 731-1449 - Substitution: 931-1449A $17.36 on their site.
I found the same part cheaper at eReplacementParts.com - $20.62 including shipping. The part from Sears would have been $26+. eReplacement has an "economy" shipping option, only $3.85.
 
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