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WOT (wide open throttle) When I mow I always mow WOT. I figure that the equipment was designed to get max efficacy from WOT. The ground speed I regulate with the transmission. If the governor is working right you won't over RPM the engine.

I do. I believe the manual for my JD rider says to operate the mower at WOT for best efficiency. Like you, I regulate speed with gear selection. I have no other choice than WOT on my push mower.

I run WOT with my John Deere X520. Doing it this way keeps the fan on the transmission turning the fastest thus keeping the transmission cool.

All mowers should be run against the Governor.
It is not really ruining at WOT it is running at the speed the engine manufacture intended for it to run.
If they wanted it to run slower they would have set the governor at a lower speed.

I think that is why some people want to throttle down is they view it as wide open when it is not it is where it was designed to run.

Gas engines, especially those with air cooling, run WOT, yes. My Deere, a diesel with liquid cooling, I run at 2300-2500 rpm while mowing. Running the engine faster doesn't increase cutting performance but it does increase fuel consumption about 20%.

reynoldston said:

WOT (wide open throttle) When I mow I always mow WOT. I figure that the equipment was designed to get max efficacy from WOT. The ground speed I regulate with the transmission. If the governor is working right you won't over RPM the engine.

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Small engines were designed to run with max throttle position. It is critical for proper air flow and oil circulation, thus keeping your engine cool. Don't forget to keep those air fins clean on the engine?

littlesteve said:

Small engines were designed to run with max throttle position. It is critical for proper air flow and oil circulation, thus keeping your engine cool. Don't forget to keep those air fins clean on the engine?

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Good point, clean fins and no dirt or grease build up on the engines help them run cooler.

Yep. Keep 'em clean, run good oil, and wind 'em up. May as well break at 3000 instead of 2700!:laughing::biggrin:

As a few have said, the speed governer limits the rpm to the best speed for the particular engine/blade design. It is NOT max speed, but instead "best speed". All mowers really should be run at the max governer speed, otherwise you're cutting either cutting efficiency, fuel-efficiency, or even cooling-efficiency.

Steve

Let's not confuse "WOT" with setting the engine speed control to the maximum position, as is required. The governor will maintain the the engine speed at the design RPM by modulating the throttle opening according to the load. At maximum load the throttle will be wide open to maintain the RPM. If the load increases beyond that, such as getting into thick, tall wet grass, the engine will slow and stall even at WOT. On an engine without a governor, at WOT with no load, it will over-rev and eventually destroy itself. It's not the same thing.

Wow.......eye opener....guess I`ll change habits now.....giver more throttle..maybe even WO

Yeah, you might get away with using 3/4 throttle most of the time because the governor will keep the revs where they're supposed to be, but as soon as you go up a hill or run into thicker grass, it will slow down because you haven't set the throttle lever to full speed.

oldyellr said:

Yeah, you might get away with using 3/4 throttle most of the time because the governor will keep the revs where they're supposed to be, but as soon as you go up a hill or run into thicker grass, it will slow down because you haven't set the throttle lever to full speed.

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hmmmm...my first reaction to thicker grass is to slow the ground speed... s`pose I`ll still have to do that even at WOT....I just thought running WO would put more strain on the motor ..but I have read different, and I`m not above learning new things.....I`m glad I popped into this thread..:thumbsup:

gtbobcat said:

T....I just thought running WO would put more strain on the motor

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Again. it's not WOT per se, it just allows the governor to go to WOT if the load demands it to maintain the proper RPM. If you put the throttle lever to a lower setting where the engine actually runs slower, not only will you not have maximum power available when you need it, but the mower blade(s) will be running slower and not cutting properly. Lawnmowers are constant speed machines designed to run at a specific engine RPM and blade RPM.

I got it now..... engine runs for the load placed on it.. if its not at full throttle I`m not getting whats needed when that load increases...I see now why my new push mower has no throttle cable....and I thought it just idled too fast....

According to my manual I am supposed to run WOT:thumbsup:

i know my hydros hate low rpms...it makes them struggle......also with the tranny fans ..you need to keep them whirring away...............but with manuals ... i drop rpms a little to shift and engage the blades..

gtbobcat said:

hmmmm...my first reaction to thicker grass is to slow the ground speed... s`pose I`ll still have to do that even at WOT....I just thought running WO would put more strain on the motor ..but I have read different, and I`m not above learning new things.....I`m glad I popped into this thread..:thumbsup:

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When my diesel tractor hits a stand of high, tough grass, I can see the RPM's begin to drop on the tach so I immediately reduce ground speed until the RPM's build back up to where they were, and gradually increase ground speed back to where it was. Having a tach is a great asset to keeping your engine on the power peak.

thats another idea swimming in my brain....a tachometer for every mower!.....ill have to buy in bulk to get a discount :frown:

There are digital phototachometers available that will tell you your no-load RPM. Not bad money either, if I recall, about $80.00.

I HAVE ONE OF THOSE...I JUST LIKE GAUGES ON MY MACHINES :biggrin:

benski said:

There are digital phototachometers available that will tell you your no-load RPM. Not bad money either, if I recall, about $80.00.

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That's way too much. Try this:

Small Engine Tachometer Hours Meter

oldyellr said:

That's way too much. Try this:

Small Engine Tachometer Hours Meter

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Sure like the looks of that tachometer and the price doesn't look bad. This looks like something I could use on my tractor with the snow blower. I have hour meters on all my rider mowers and ATV's because this tells me when I need maintenance.

when I'm cutting grass, it is wide open.

Well I cut the grass......but I`m still a little shy to open er all the way....I was maybe 1 notch under WO ..more than usual but still not WO..I`ll need to do the field soon..maybe then...it`s wide open...fewer distractions

There's no quicker way to negate your warranty than to show up with a problem and admit you haven't been running your mower with the engine speed control lever full up.

As has been said, this lever does not control your throttle directly, it controls your governed engine speed and the throttle opens and closes automatically to meet the demand. Your mower is designed to run with this lever fully engaged in order to obtain design RPM for engine cooling, hydro cooling, and blade/deck performance. To run with the speed control lever part of the way up tortures your machine. That's why every mower manual tells you to push it to the stop.

If you're OK with the engine and blade noise from your machine without hearing protection, you're not doing it right.

It`s....it`s...just hard for me to imagine I`ve been doing it wrong all those years...and only luck has prevented me from having troubles...it`s gonna be WO from here on end..and yes the ear protection is coming out...a big :thumbsup: for everyone showing me the way...sure glad I popped into this thread and to the thread starter for posting the Q

benski said:

Yep. Keep 'em clean, run good oil, and wind 'em up. May as well break at 3000 instead of 2700!:laughing::biggrin:

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engines o0n most small mowers run at 32 hundred rpms

I stand corrected, when I can stand at all...:biggrin:

Run that thing wide open. When I was a service tech many moons ago, our Briggs trainer as well as the reps from Lawnboy, Generac and MTD all told us to make sure we advised our clients to run their units WOT.

I ran it WO....wasnt much of a change from when I didn`t.. noise or engine speed.......but the ear doent pick up a minor increase in rpm`s now does it...I must of been close to WO all those years

Your RPM would not be any different under lighter load conditions. However, if the control was not set to maximum, it would have bogged down sooner if the load increased because the carb could not go WOT.

I run "WOT", but not out of choice.

Bloody modern technology! Give me a throttle any day

oldyellr said:

Your RPM would not be any different under lighter load conditions. However, if the control was not set to maximum, it would have bogged down sooner if the load increased because the carb could not go WOT.

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I see where you may have a point with a self-propelled push mower, but the blade still needs to run at its optimum RPM to cut properly, so the governor does that and applies throttle up to WOT to maintain the speed depending on load. You achieve nothing except mangled grass by running the blade slower. However, you probably would prefer to control your forward motion speed, is maybe what you're getting at. I guess your mower doesn't have that capability, but the more expensive Honda models have variable speed drive.

oldyellr said:

Your RPM would not be any different under lighter load conditions. However, if the control was not set to maximum, it would have bogged down sooner if the load increased because the carb could not go WOT.

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Thats where I found the difference !! I only slowed to make tight turns...not b/c the grass was too thick in places.