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This should apply only to those who have an engine where you can vary the operating speed, it does not apply to mowers that run at a set, constant speed.

Every mower or tractor I have owned that had a throttle that controlled engine speed clearly stated in the manual "always mow at full engine speed", but many times if I was mowing dry grass or grass that wasn't hard to cut, I never used more than 80% of throttle. Supposedly using 80% of throttle gives the engine a workout (especially important in a small diesel) but doesn't stress the engine enough to cause problems down the road. I posted the same query on TractorbyNet several years ago and the responses were mostly "run at 80% maximum throttle when you can and save the remainder for an ugly day" :laughing::confused2: which I interpret as meaning when you have to cut fast to get ahead of the rain that is coming give it full throttle. Any thoughts?

I always run at full throttle. These engines are made to run at full throttle and run best there.

I run my John Deere at full throttle.
I have had zero problems doing so and also the hydrostatic transmissions on these and other machines need the higher rpms to keep the transmission cooling fan working at maximum efficiency.

They are also designed to cool best at full throttle!

Diesels of today can run at idle or full governed RPM.......it will not hurt the engine......so Please do not Worry........just make sure you service the Engine every 200 Hours.:confused2:

I mow at full throttle most of the time, I will slow down some if doing alot of trimming in close quarters. I don't think it matters much if you keep the rpm's up most of the time, idling excessively can cause problems though.

My tractor and tractor type mowers have tachometers with PTO speed marked... and that is generally just a bit less than WOT... probably around 80%...
My mowers and decks have blade tip speed listings and I generally try to find the rpm that achieves the blade tip speed... Faster gets a better cut generally & is less load on everything... but I have never seen it necessary to run any engine at it's maximum RPM... the governor is usually going to allow a top RPM of just a little more than you have to run at... :smile:KennyV

KennyV said:

My tractor and tractor type mowers have tachometers with PTO speed marked... and that is generally just a bit less than WOT... probably around 80%...
My mowers and decks have blade tip speed listings and I generally try to find the rpm that achieves the blade tip speed... Faster gets a better cut generally & is less load on everything... but I have never seen it necessary to run any engine at it's maximum RPM... the governor is usually going to allow a top RPM of just a little more than you have to run at... :smile:KennyV

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Well Kenny my older tractors have the tachs with pto speed marked as you mentioned. My newest tractor has the epto option which allows 540 rpm at a reduced engine speed of 1740 rpm. This works well for an MX6 brush cutter in most cases. If I have to cut something really heavy I use the regular setting. When brush cutting I can run much lower as I am not concerned about high tip speeds and fine cuts. The 4520 with ehydro and upgraded cruise, digital tach and speedometer does add some nice features. But I digress, I thought this was a lawnmower forum.

jenkinsph said:

I thought this was a lawnmower forum.

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It is a Lawn Mower Forum...:thumbsup:
But the original question is "What RPM do you mow at?":biggrin:

I mow with a Kubota Grand L tractor... with a 7 foot finish mower & a 6 foot rotary mower... and a Large ZTR mower... all of which have tachometers and recommended blade tip speeds...
My smaller tractors without PTO indicators leave me running just a bit lower than max engine governor speed... :smile:KennyV

my grasshopper[kubota diesel] the manual states the no load rpm is 3000 and the pto is 3100max.it doesn't have a tach. but does have an hour meter.I usually run it at 3/4 throttle. when I used to mow with my Yanmar w/finish mower it was 2200rpm. russ