Bought a Jenkins super duty mower and it is rated for 14-26gpm @ 3500psi. My 90XT on low flow does 21gpm @3000psi and my high flow does 30gpm @ 5000psi (flow can be varied with lever in cab). Which would you run the mower on? What precautions would you take if on high flow (flow control, relief, gauge in line to monitor pressure, ect.). Will there be much difference in performance from the 21gpm to getting 26gpm dialed in on high flow? Thoughts or experience is appreciated. Thanks
my guess is that it all depends on the conditions. If you’re cutting tall thick heavy wet grass and it does the job in low flow mode, then just use that. If not, bump it up to high flow.
How much of a gain in performance would you expect in the mower from 21gpm to 26gpm?
I would set it up for low flow first. It will use less fuel and for cutting grass, I doubt the added power of HF would make a difference.
90%+ of my work will be clearing bush (75% Hardwoods 25% softwood) along fence and pasture. No plans for grass really.
There is a 24% increase in flow from 21gpm to 26gpm. Would I see that in cutting speed also?
Can you turn the pressure down on high flow?
No, but I can adjust the flow which will reduce pressure doing the same amount of work.
I don't think pressure goes down from lowering flow unless the control does both. As an example you don't lose lift capacity if you lift the load slower. Flow just controls speed. Pressure gives you the power to do the work.
Resistance to the flow produces the pressure. A friend of mine has a mower with a pressure gauge on it. A gauge would be a good idea. Pressure gets too high, slow down.
I miss understood what you cutting. If your cutting small trees and shrubs you would benefit from the higher flow, but if the mower maxes at 3500 psi how do you use high flow with 5K psi and keep from damaging the hyd motor and hyd lines? I have a 95XT instruction manual here somewhere, I was going to look up the high flow psi portion and see if there is any info on it. I also believe that the psi will be maintained through out, but even if it doesnt you would have to know where 3500 psi is on the throttle. You have about a third more psi potential than the mower can handle, wouldn't be good to blow the seals out of the new mower. I think by trying it on low flow would be safer for the attachment, if your not happy with performance, you can then work through the high psi issue. If it works on aux. flow, it doesn't really matter.
Lower throttle doesn't lower pressure. You have to have a way to limit max. pressure.
I had a similar issue with my snow plow. The angle cylinders were rated for 2500psi. My machine runs 3500psi. Yeah it worked fine most of the time, until it hit resistance like the turn stops, then the pressure spikes and blows the seals out of my cylinders. Not fun. Turning down flow won't change the pressure when you hit resistance. With a brush mower, you will and that over pressure could cause damage to the mower motor. Even if the mower has a pressure relief valve to prevent over pressure. Tripping a relief valve generates heat. You're turn that extra power into heat you don't need. That can damage the mower too and also over heat the fluid and your machine. There's really no reason to run it with high flow, your low flow is well within the mower spec and it should perform as rated.
It takes both flow and pressure to make power. Power is flow X psi. You can calculate your hydraulic hp as follows: 21 gpm x 3000 psi / 1714 = 36.75 hp - low flow 30 gpm x 5000 psi / 1714 = 87.51 hp - high flow 26 gpm x 3500 psi / 1714 = 53.09 hp - mower max So your high flow setup has over twice the hp of low flow. And 34 hp too much for the mower. More than you really wanted to know, right?
Thanks all for your info and time. I ran the mower on the low aux. and was very happy with the performance. No use trying to fix something that works great.
Good to hear it worked out.
The very first thing I would do is show the wife how to run it.....just like she tried to show me how a vacuum cleaner worked.
No way then I will never get to play in the skid steer, she will always want to do all the skid steer “work”