Hydrostat mower moves slow and then stops

slow030

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Recently picked up a Craftsman rider model 917. 273160 with hydrostat. Runs great, but was moving slow, and after mowing about 15 minutes it stopped moving. I replaced the drive belt, but no improvement. Replaced the fluid in the hydrostat, again no improvement except after warming up it never stopped moving completely, just slowed to a crawl. What can I do to fix this?
 

bertsmobile1

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Did you bleed he hydro ?
What oil did you use ?
Which hydro are we talking about ?
Is the tranny quiet or growls like a mountain lion ?
Did you check the input pulley splines ?
 

slow030

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To bleed, I raised the rear off the ground and ran it back and forth from forward to reverse multiple times, is that the proper procedure? Used synthetic 20w-50. Not sure what hydro, tag says hydro-gear then has a bunch of numbers. It is quiet for the most part. When it stops moving and I continue to push on the lever it makes some growling noise, but quiets down if I release the pressure on the lever. No, didn't check the splines on pully shaft.
 

bertsmobile1

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Purging should be done at the lowest speed the engine will run at .
Otherwise you just froth up the oil
Give the purge a second try .
My rough bush test for a hydro is to try and roll it off m tilting trailer without releasing the bypass valve.If I have to pull hard, then the tranny is good
If it will just roll when pulled lightly it is OK
If it races down & runs over my foot it is gone.
The growling is bubbles of oil blowing out the side of the cylinder / valve plate interface
 

slow030

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Bleed again at low engine speed. Noticed that when in forward both wheels turn, then after a few seconds the right one stops. Same in reverse, the right one stops. Went back and forth about 10 times. Without releasing the bypass, it takes some effort to push, I do have a tilt trailer, may try that if I ever get home before dark.
 

bertsmobile1

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Sounds like you are getting there
Some boxes purge like a dream in less than a minute .
The the exact same model box on the same model mower takes 1/2 a day
I have gotten so frustrated at times I hooked up my sump pimp to the breather and put the box under vacuum to pull the mongrel air out .

So do not be surprised if you need to purge a dozen or more times with a couple of hours rest to allow the oil to settle.
 

slow030

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Have tried bleeding 8-10 times, still the same, both wheels turn then after about 5 seconds the right wheel stops. Should I keep trying to bleed, or try something else?
 

4950cycle

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Did you ever get it working ?
 

slow030

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No, don't have the room to work on it this winter, I think I will take it apart next spring and see if the pump is bad.
 
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