Where to run 7610w/HST

[NC Bota]

I have perhaps a dumb question on the best power settings to run my B7610 and also want to get an understanding of how a HST works.

First the HST. Kind of like an automatic transmission, but not quite. The more you push the pedal the faster the wheels go. When the pedal is fully pressed is there a sort of "lock up" that occurs that would produce less wear than when it is partially depressed? I am assuming that at slower speeds there is some sort of slippage that occurs in the transmission to produce slower speeds, but am not sure.

So, if my assumption that the least amount of slippage occurs when the HST pedal is fully depressed is correct would it make sense to keep the engine throttled back to where you run with the HST fully engaged (pedal pressed down fully), and if you want to go faster increase the throttle setting. Or is all this moot and should I run the throttle wide open all the time like the delivery guy said and vary the tractor speed with the HST?

It seems to me that the wear and tear on the tractor (and we have not even talked about the speed of the hydraulics yet) is greater the faster you run the tractor engine and that you can extend the life of your tractor by slowing the engine down to where you need it (as long as it is not being loaded too heavily).

Thanks in advance.

 

[Bulldog]

My thoughts on this is that the designers of the tractor intended on it being ran at the rated PTO speed when it is being used and the ground speed is to be controlled with the HST pedal. If they didn't want you to control the ground speed with the pedal it would have been a go or stop pedal for a lack of better words.

 

[handyman]

I agree with bulldog they were speaking of full throttle with rear pto and attachments being used. There is no slippage with the hst its like your automatic trans. in auto sort of. The harder you press peddle or go peddle the faster or slower it will go. It does not slip. I dont run mine full throttle only about 3/4 when mowing with a mid mount 60 inch mower. I have a B7100 hst. handy

 

[handyman]

NC bota forgot one important thing there is never a dumb question on this forum. Welcome to forum. handy

 

[KubotaTech]

HST transmissions are sort of like automatics in a car, but not really. There is a pump and a motor, so whatever fluid is expelled from the pump, the equal amount is pushed through the motor. When you are at neutral on the pedal, there is not any fluid being pumped to the motor, and as soon as you move the pedal, the fluid starts flowing. There more you move it, the faster it goes. But like anything else, you have to give something away to get something back. The farther you move the pedal, you get more speed, but less torque. This is why when you are starting from a dead stop with a heavy load, the tractor will take off with more power when you barely move the pedal. If you slam on it like a car, it will stall out. If you run your tractor's engine at higher speed, you get more power and you also get more charge pressure, to a certain point. There is also a charge pump in an HST that keeps the drive pump and motor full of oil at all times. If you have a higher engine speed the charge pressure is up to the point of the relief kick out. This is why it is extremely important to keep your fluid level up to the top at all times. If you dont have fluid, you dont drive and you dont lubricate all of these previously mentioned parts. THAT is how you destroy a hydro.

 

[NC Bota]

Thanks for all the replies. I agree that if I am running something off the PTO then the engine is run at the necessary speed. Is there any negative to running the engine at reduced speeds when you are not using anything driven by the PTO? Seems that would reduce fuel burn a little if nothing else.

Thanks in advance.

 

[handyman]

Kubota Tech thanks for explaining that. As I always say I cant explain what I mean most of the time. Thats why I am glad it is people like you ,vic,bulldog, aqua.traildust and cant name them all. Thanks again we have a lot of knowledge on this site and proud to be a member. Cant forget dusty its not much he hasnt made rebuilt to work the way he needs it to with his pics.handy