Mid-Mount Mower mowing speed

[MHarryE]

At your tractors age (22 - 24 years) and without your knowing its service history, I would suspect worn hydro components. First thing is to check propel pressure and make sure it is reaching 3500 psi. You probably already know your tractor was built by Hinomoto. If your OMM gives any indication where to check propel pressure, plumb in a gauge and see what kind of pressure you get when the tractor stalls out. There should be a way to adjust the high pressure relief (possibly 1 relief for forward and 1 for reverse) to compensate. I can't think of any real wear point in these direct acting reliefs but springs can lose tension with time and heat, and the relief pressure is set at a given flow rate through the relief. If the pump is no longer capable of producing this flow, the relief will need to be readjusted to compensate.

 

[filltbo]

Thank you all. Terrific advice and insight for this newbie! Based on your inputs I did a couple of tests and I think these are pointing to the high pressure relief valve.

1. My rpm drops about 150 rpm when I engage my mower deck on the driveway. So I guess that is a lot of extra load on the hydraulics!

2. In low gear I can climb a VERY steep hill without issue (mower disengaged). The hill is steep enough that I would most likely tip over if i drove on it sideways (it climbs about 10 feet in 30 feet distance).

3. In medium gear i get up about 9/10th of the way and then something between my feet starts to whine, If i throttle up to get my motor rpm up to 2500 it just whines louder, but the tractor does not move. A friend of mine (heavy equipment operator) said that he would think the tractor should climb the hill with no issue in medium range. It should like most of you would probably agree.

4. The tractor behaves the same forward and in reverse.

mHarry suggests that the high pressure relief valve can be adjusted after testing the pump output pressure. I will get a gauge and see if I get more than the 3500 psi needed. I FINALLY found the high pressure relief valve assemply in my repair manual. Looks like I will disassembling part of the tractor again!

AGAIN... many thanks to all of you. This helped point me in a useful direction to test this issue. Its a lot of fun to take a non-functioning pile of steel and bring it back to life!