Working Engine RPMs

[Sysop]

I'd say it's a different sort of whine. All hydraulics do have various amounts of whine sounds to their operation. The whine I've always assumed I was being told to avoid is when it's dragging the engine RPMs down and gets louder as load increases and RPMs decrease (i.e. trying to pull a big hill in mid or high range without letting off the go-pedal some to let it go to a lower range inside the HST). They will whine when under lots of load, that's normal for all hydraulics. But if all you're doing is moving it around there shouldn't really be much load, so if it's wining, give it more juice, less go-pedal, or try a lower gear range. You'll never eliminate hydraulic whine, the goal is simply to operate the machine in a manner that minimizes it.

Only time my HydroGear on my lawnmower makes any noise at full engine RPM is when I change speeds rapidly or am on a big hill. On big hills I back off the HST some to let it climb slower and I avoid rapid speed changes. If I drop my mower RPMs down the HST starts to whine rather loud at about halfway through the speed range selection.

 

[Mark Headley]

I find my DK45SE HST will cut every bit as good at 2-2100 rpm as my CK30HST did at 2500.

 

[murphy1244]

You will feel the engine chugging when you don't have enough throttle.

 

[Sysop]

I find my DK45SE HST will cut every bit as good at 2-2100 rpm as my CK30HST did at 2500.

Are there any difference between the two as to what engine RPM the PTO reaches it's 540max? Tip speed is a big part of getting a good mow.

 

[murphy1244]

My Massey will hit PTO speed at 1500 RPM

 

[Sysop]

My Massey will hit PTO speed at 1500 RPM

My Father in Law's MF135s both hit PTO at more like 1700 or 1800 if memory serves. One of his 135s is a 3cyl and the other a 4cyl. I like old machines, but I don't like the variations in specs between like models. Brother in Law has an old Ford that he's always got problems laying hands on the proper parts because his model is some sorta oddball that parts changed a half dozen times during the production.

I was just thinking a variance in the engine RPM that achieves PTO speed could be why he mows as good at lower engine RPMs. Various tractors are all over the engine RPM range to get the PTO to 540, some low, some high, just depends on the model (and sometimes not even that ).

 

[murphy1244]

Well the DK 45 is a 4 cylinder and the CK a 3 cylinder.

 

[Sysop]

That definitely makes a difference in where the power band is within the RPM range for the engine, which is what manufacturer's use to determine what gearing to use to get the 540RPM at the PTO to be right in the middle of the power band of the engine.

 

[murphy1244]

You would think so.

 

[Sysop]

I'd still keep the RPMs up to minimize strain on the HST