Operating speed

[Glades Cat]

Hello folks. I’m new on here and have searched for some info and can’t find it. I just bought a new Ariens mower.
Question...What power setting should I run the mower at? Some folks say wide open throttle, others say it’s OK to run at reduced power. Does this also affect the Hydro Gear drives? Also, engaging the blades. Should it be done at WOT or reduced power, the next increase throttle?
Sorry if this has been answered before. I couldn’t find it.

 

[Rivets]

When operating the unit, blades engaged, you should always be at full throttle. When engaging the PTO you need read the owners manual, as different manufacturers have different speeds for their equipment.

 

[fixit1ddh]

Most dealers and manufacturers say wide open. When I work for a dealer in 70's that's what I'd tell customers. Because that's what I was told to tell them. I do not mow wide open and I kick blades in on All our zero turns just off idle. And idle it down before turning blades off. Wide open is good for parts sales. But I have only been a mechanic since 1968.

 

[Glades Cat]

Ok, good info. Yea, I’ve built quite a few engines, race cars, hovercraft, boats and airboats over the years. I can see the correlation when engaging the blades on the mower to popping a clutch at WOT on a car. That’s a lot of stress.

 

[bertsmobile1]

Mowers are not cars so most of car tech is not directly applicable
1) hydros are designed to run at a fixed speed
Running them slow will accelerate wear
2) blades are designed to run at a particular speed running them slower will usually give you a poor cut unless you sharpen the blades to a knife edge
3) the air cooling is designed for a specific air flow rate, running the engine slower causes it to run hotter ( sounds counter intuiative but it is all about the R value which is the rate of heat exchange
4) Mower engines are governed , to run at a speed just past the peak torque so when you put extra load on the engine , say in thick grass , there is extra torque available as the engine slows down to help it speed back up again as all of them use fixed timing apart from the EFI engines .

 

[fixit1ddh]

Ok, good info. Yea, I’ve built quite a few engines, race cars, hovercraft, boats and airboats over the years. I can see the correlation when engaging the blades on the mower to popping a clutch at WOT on a car. That’s a lot of stress.

When I run My engine up against the governor 3600 or down at approximately 3000 rpms. I check oil filter temp and it's running 25 to 30 degrees cooler when I runing it at approximately 3000 rpms. Also for the same area I cut I save approximately 1 and a half gallon of fuel. That's cutting between 5 to 7 acres at approx the same height. That is what I experience with My kohler 7000 series engine.

 

[Hammermechanicman]

Ferris recommends engaging blades at WOT and mowing at WOT. But what do engineers know (sarcasm)

 

[slomo]

When I run My engine up against the governor 3600 or down at approximately 3000 rpms. I check oil filter temp and it's running 25 to 30 degrees cooler when I runing it at approximately 3000 rpms. Also for the same area I cut I save approximately 1 and a half gallon of fuel. That's cutting between 5 to 7 acres at approx the same height. That is what I experience with My kohler 7000 series engine.

Yup, lower revs saves fuel.

Wouldn't worry about the oil temp drop. You actually want the oil nice and hot to burn off any moisture in the oil sump. Now if you get over 300F temps, let's talk again.

Can thank the Democrats for the extra gallon and a half you use at 3600. Call Sleepy Joe and tell him he owes you $7.50 when you cut your grass LOL.

Briggs and Stratton states run at MAX revs all the time. You get max cooling and lubrication doing this.

 

[fixit1ddh]

I have briggs that I bought new that are over 50 years old. And not much have they been run at governed speed mostly around that 3000 rpm range. Aluminum bore. None use any oil or smoke. On a 1991 chipper shredder with a 5hp flathead briggs. It doesn't smoke or leak oil but it has to run a 3600 rpm and it goes through oil like water. My 56 john deere 70 diesel says run at high idle at 1150 rpm. Never ran it over 1000 rpm and it still runs and starts like she was built yesterday. I do not and never agreed with company's that say run them at governed speed all the time. I think they like selling parts. My old briggs that I use regularly and run at reduced speeds will probably be running when there will be no fuel to put in them any longer. Knock on wood I have never had a small engine or any engine ever go belly up. But I have worked on a whole lot of them that were run by the book and there rods were hanging out the side of the block.