Buying Advice Done with hydrostatics

[fitterski]

THAT may have been on it when bought, I don't know but I'll find out. The little bugger when he was just a wee lad I would bend down almost to my knees and tap him on the head "how's dad's little son today?" Now around 6 foot 13 and with arms like my WAIST he does exactly the same thing to me

He bought it like that, doesn't know if was the original paint job or not. He's swapped out the entire drivetrain but left the appearance close to what it was ...and he's a long way from fini$hing it.

 

[ruffdog]

Fans are flywheel connected so cooling air is proportional to engine rpm as is heat generated.

Well, that is sorta correct. The problem is, these engines are governed so the throttle is connected to the governor, not the carb or fuel pump. You may have the "throttle" at half speed, but under load, the governor is WIDE open. In this instance, the cooling fan is at half speed but the engine is wide open and making max heat. Part throttle should not be used under a load.

 

[4570Man]

Well, that is sorta correct. The problem is, these engines are governed so the throttle is connected to the governor, not the carb or fuel pump. You may have the "throttle" at half speed, but under load, the governor is WIDE open. In this instance, the cooling fan is at half speed but the engine is wide open and making max heat. Part throttle should not be used under a load.

I’m not understanding how that works. The engine can’t be at max output and only 1/2 speed unless max power happens at max speed which it doesn’t for air cooled gas motors.

 

[ruffdog]

I’m not understanding how that works. The engine can’t be at max output and only 1/2 speed unless max power happens at max speed which it doesn’t for air cooled gas motors.

The governor tries to maintain the rpm that the hand throttle is set at. If there is a higher load, like deeper grass, the governor will have to increase the throttle to achieve that same rpm. So, it is possible to operate at half RPM but the governor has the engine at WOT.

 

[ruffdog]

How a small engine governor works:
How does a small engine governor work? | Briggs & Stratton

Also, if your engine has a oil pump that has higher output related to rpm, you might be at WOT but at a lower oil pressure because the rpm is at a lower speed.

 

[fitterski]

There's been discussion about cooling problems on these trans-axles, that the fan on the drive pulley is there for that. IT of course is a 25 cent piece of plastic, what would seem no less useful are the more expensive cooling fins on the axle housing, of which on my Hydro-Gear trans-axle there are NONE.

Another tid-bit, I drained the oil and contrary to what the dealer had told me (clean & full) it was pitch black and about 1.95 litres in all. There was no foaming nor any sign of water contamination. I refilled with new oil to absolutely no avail, I can hear the pump/or-motor cavitating same as before and there's still no explanation as to how this can come about during one winter of sitting still.

More, one of my neighbours had the same problem with another make and threw it out last year. She's a widow and is now contracting out instead, I had thought she was just fed up with bouncing around in the sun with a mower herself. Not so.

 

[fitterski]

The governor tries to maintain the rpm that the hand throttle is set at. If there is a higher load, like deeper grass, the governor will have to increase the throttle to achieve that same rpm. So, it is possible to operate at half RPM but the governor has the engine at WOT.

Everyone who has operated a mower can tell from the sound when the thing is biting more than it should. With a regular transmission and no governor you then ease off on throttle which unloads the blades and slows down the machine. With a governor and a trans-axle you ease off on the speed pedal which reduces the bite and accomplishes more or less the same thing. The governor is nothing more than an rpm biased/governed throttle, the user sets the governor instead of the throttle. Throttle position NEVER determines the rpm, governor or no governor, you need the combination of throttle position AND load for that. It's like torque, the engine may be able to develop it but without resistance there can be no torque.

 

[ruffdog]

^^^^?

 

[fitterski]

^^^^?

The governor sets an rpm command, it will maintain it IF it can depending on the load. The rpm is determined by throttle position and load, not by the governor. When you hear it overloading and usually shuddering you reduce speed which reduces the feed rate i.e. the load and then the rpm command can again be satisfied under the new lesser load.

 

[searcyfarms]

I have had 4 hydros since 1991, never a problem with ANY of them, 3 fords, one deere the two early fords were eatons/Tecumseh gear box - not sure on the 3rd ford nor what model is in the deere. The unknown ford hydro was a GT75 and the Deere is a 2210 - changed their fluid/filters and all had/have fans for cooling on their drive shafts. No way you could ever talk me into going back to a gear shift - I never once thought about engine speed - have used them all for gardening/pulling loads from wagons to tillers - dragging/blading - mowing - loader work - so they have been used and never an issue. I do think the smaller uncooled, non heavy duty units are prone to issues, my sister purchased a zero turn deere from home depot and they have replaced 3 hydros in it in 3 yrs - they are mowing 4 acres and I just don't think that deere was made for that.