1782 3 point lift capacity
 

I put a 3 point on my 1782 and bought a Brinly 3 point blade recently. The blade wasn't cutting in too well, so I hung a couple 42 LB. suitcase weights on it. I had to rev the engine up to about 3/4 throttle to lift it. It has a fresh oil and filter change and cleaning of the rearend. The oil and inside of the rearend looked great when I changed it. I had the same issue with my tandem disk. I realize these are both heavy implements, but the manual for the disk says it can hold concrete blocks in the frame. I assumed that most garden tractors were capable of lifting that much if they mentioned it in the manual. Is it time to look for a problem with the charge pump or was I asking too much of the hydraulic system?

My 1450 will (slowly) lift ~300# on a sleeve hitch aerator at full throttle. However the weight is very close to the tractor, about .75 feet , which would be 225 ft lbs of torque. You hang 120 pounds 2 feet away from the tractor, that's about 240 ft lbs of torque needed to lift. Sounds about right that you would need at least 3/4 throttle to lift that.

The charge pump is just a small gear pump. It doesn't produce much flow but it should produce about 900 pounds pressure if I remember correctly. Running the engine faster doesn't produce more pressure, but it does produce more flow, which would overcome a weak relief valve. I'd suggest putting a gauge on it and checking relief pressure. The service manual tells how to check and adjust the pressure.

I had a similar issue with my 2072 and it turned out to be a seal input shaft seal. I'm guessing it was acting as a relief valve when i was stressing the system. Replaced the seal, tightened up the trunion and it's like a different machine!

Maybe take a look for leaks and check the fluid levels to make sure it's not going down? I was going to borrow some gauges to check the pressure but after replacing the seal i'm more than happy with it.