I have a 190, it goes a little bit faster in reverse than forward, I am guessing it either needs a new pump or drive motor? My guess would be drive motor, but I am not 100% sure. I'm anxious to hear what people say. It seems that aftermarket pumps for the 200 and 400 series tractors are readily available, but maybe not so much for the earlier tractors.

 

i just replace my hyd motor on my 155. because it was slow moving forward/reverse.
now it works great.
i brought aftermarket
http://www.ebay.com/itm/111248280046?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

 

No it not right pump that pump is for counter clock wise rotation CCW you need CW rotation. Shaft on that pump 3/4 that may be to big. .61 cubic inch pump to much oil flow for orbit motor used to propel tractor.