Am I Destroying My Brand New Zero Turn Gravely Mower???

If you all recall, I did a video about a year ago showing my 3 month review of the Gravely ZT HD 52 Zero Turn Mower. I recently received a comment from a viewer of that video who said I would be damaging my clutch by engaging the mower deck at full throttle. I decided to do a deeper dive and find out if that is really true! Thanks for watching!
#gravely #zeroturnmower #lawncare

[@darrelbiolo2596]

I own a gravely pro turn 160 and a ZT/HD 48” I engage at full throttle and disengage at idle

[@krflyguy2117]

Your review video helped me make my decision to get a Gravely 60". I just was reading the manual a couple nights ago and it agrees with you and state to engage the blades at full throttle. That coincides with what my dealer said to do. I absolutely love my Gravely ZT HD. Thanks

[@travisricks3436]

I have a new Gravely ZT HD 60 with the Kawasaki FR730V. I always engage the PTO at full throttle and always disengage the PTO at the lowest engine idle. Doing that will save the clutch.

[@jamesWilliams-ch9sn]

I have the ariens Apex 60 . Love it . I always engaga at high rpm . Disengage at low rpm

[@trunkmonkey9417]

I have the same ZT 52 HD. About 80 hours and had to replace the deck belt (rear PTO/blade drive) because it rolled/burned and delaminated. ( I thought I caught a wire or something in the blades) Had vibration and a "slapping" noise and looked down and saw the belt was oscillating/flapping. Shut it down, lifted the plate over the deck and saw the belt was twisted, stretched (loose) and chunks were missing. I suspect I may have had some debris caught between pully and belt (I have some bamboo that I have tried to cut) or that I have engaged/disengaged the PTO at other than full speed without being aware of doing so. I am pretty certain it was my ignorance/negligence, and after replacing the belt, I will be making certain I am at full throttle when I engage/disengage, and I do not attempt to cut anything but grass. (the bamboo will meet the tip of my shovel...) $100 a pop, for a belt is more than I want to pay per 100 hours...

[@chrisprange5347]

the belts flop around and get loose at low rpm’s and can break or jump off the pulleys always full throttle this was a really good topic

[@thebradleysoncatbirdhill6849]

Thanks for watching, Chris!!!! What you said has been pretty much the consensus from all of the techs I've spoken to who work on Gravelys!

[@SamW604]

Thank you. I often wondered about this question and engaged my Gravely ZT XL 42's PTO at mid throttle with no problems. However, now I will only engage it at full throttle.

[@thebradleysoncatbirdhill6849]

Thanks for watching and your comment! Amazingly, I'm still getting almost daily comments on this video.

[@dennisschofield3357]

Thanks for the video. I just purchased new ZTX 42 and am following the manual and the delivery mechanics instruction and am engaging the blades at full throttle. Thanks for bringing it up.

[@patricksiebert1047]

Then do you bring back down to idle before disengaging the blades?

[@stevenlong32708]

I own a Toro zero turn and the manual plainly states to have full throttle before engaging the PTO

[@malcolmh5736]

I've had my Gravely ZT 42 for several years. I've always engaged PTO at higher but mostly at full throttle but I typically bring speed to slow or stop but engine at higher RPM. I've never had any issues whatsoever. There has never been any belt noise. Nothing has broken ever. To me, it feels intuitive to engage at full throttle and reassuring that the manual you read states that. I just sold the ZT 42 and getting the new 2023 ZTX 42. The only problem I had with the old ZT 42 is the front welded frame broke and had to be re-welded but they seemed to have fixed that in new model. I agree with you sir, this mower has been an unreal purchase and saves me a LOT of time! Thanks for the video!

[@thebradleysoncatbirdhill6849]

Thanks so much for your comment and for watching!!!!!

[@howardkettner]

Very interesting. Thanks for taking us to the manual for the official explanation. I’ve always engaged at full throttle until one day I got a comment on my channel cautioning me about that practice. HOWEVER, the comment was in relation to my compact tractor and engaging the snow blower - which is a completely different can of worms given the nature of driveline components, inclusive of u-joints, that are vastly different than what you’re talking about. Your video helped give me confidence about the correct procedure for a zero-turn. Thinking that I need to reference my manuals more often. Haha. Huge thanks again John.

[@thebradleysoncatbirdhill6849]

So glad you found that useful, Howard!! Love all the collaboration here in this community!

[@JamesWilliams-rl2io]

Engage pto at full . Idle down before disengage

[@aaroninks]

My Gravely ZTR is more than 20 years old, and looks new. I have always started blades at 3/4 throttle. Never at full throttle. My electric clutch has never been replaced.

[@aaroninks]

Just following up. I just read the actual owners manual for my Gravely Promaster 250Z. On page 15 it has instructions on engine blade engagement. It does say 3/4 throttle > engage blade > move throttle to fast. My mower is a 2001 model. So it may be totally different with newer equipment. But definitely worth a dig through owners manual.

[@ericminniear8130]

When I bought mine in 2019 60 inch. I was told always engage it at 3/4 rpm’s from the dealer. 👍 but I do full throttle sometimes 👍

[@Rocky-xx2zg]

Full Throttle, then engage blades, on my Gravely 460. No issues as of today.

[@dinm65]

I have the same machine with 100 hours and i love mine!!

[@mitchschenkel2214]

I was told by the owner of the mower store to engage my Gravely ZTX 42 at half throttle and no higher.

[@thebradleysoncatbirdhill6849]

Thanks for watching and your comment! My model may be different in functionality, but if I engage at anything less than 75% throttle, the engine begins to stall. The one thing that I have learned about Gravely is that their belt pulley design is unique. Engaging at lower throttle speeds actually increases the friction wearing of the belt. I am now well over two hundred hours, and the belt looks brand new.

[@leegoolsby3676]

I have a 2023 Pro Stance 32 and the first 5 hours of use had in shop twice for snapped belts. 2 issues were determined by the vendor. 1. the belt setup was incorrect for lower height settings of deck. I was cutting at 2.5 on a property when 1st belt snapped leaving me stranded. 2. I was engaging blade at lower than full throttle when blade belt snapped. I have since run the mower 65 hours with zero issues and ALWAYS engage blades at full throttle.

[@iplaymytele]

I have had my gravely for probably seven or eight years…. And I always engage the mower deck at full throttle …..! When you do it at just above its idle, it acts like it will kill the motor….

[@bigdogbrosadventures8371]

Largely depends on the deck size and rotational mass of the blades. Why have the clutch slip trying to catch up up to a full throttled engine. Half throttle is fine and less wear and tear on the drive train. Do what feels and sounds good. My Simplicity Sunstar 48" always engaged at just above idle and that mower was 25 years old with the original belts when I let it go. Maybe Gravely needs more development.

[@thebradleysoncatbirdhill6849]

Just to make sure that this was not unique to Gravely, I also checked with Xmark, Kubota and Toro dealers and service centers, and all gave the same answer ...only engage at full throttle.

[@howardrobinson8578]

I have a law care business and never engage a PTO at full throttle. I have a mower with 1300 hours and only on the second PTO belt and have inspected my pto clutch with almost no wear on it.

[@tractortalkwithgary1271]

I have always been told to not engage at full throttle. Always thought it was easier on the machine to engage and then throttle up.

[@thebradleysoncatbirdhill6849]

Hey Gary! In talking with the mechanic about this, he said the problem with engaging at less than full throttle involves the belts not fully seating on the pulleys, and with the spinning, that is what causes excessive friction/wear.

[@tractortalkwithgary1271]

@@thebradleysoncatbirdhill6849 , interesting John. That is what I like so much about you tube. You really learn a lot. Sometimes you learn that things we have learned or been taught are incorrect. Good to know John.

[@bennysbackyard9257]

I’ve wondered this same thing myself it sounds horrible but I don’t think it’s necessarily bad or harmful to the clutch it’s just the way it works

[@LK-bz9sk]

My friend who has zero turns for 20 years now and he said he always engages the blades at full throttle.

[@mikerobinson9168]

I have a Kubota 726X and the owner's manual and dealer said to start engine at 1/2 throttle and to engage PTO at 1/2 throttle. I wonder why it varies from brand to brand when most mowers use the same engines and clutches and so on? Before this mower I always engaged at full throttle on all the mowers I have owned, although this my first zero turn. But it's still under warranty so I will do as they say I guess.

[@thebradleysoncatbirdhill6849]

I agree, Mike. I've spoken to a lot of Gravely mechanics, and the conclusion seems to be that their belt drive system is unique and engaging at lower throttle speeds, which increases the wear on the belts due to spinning on the pulleys before fully engaged.

[@gratzbuck9882]

I call BS on your Owner's Manual. The stress on the deck belt and PTO clutch at startup, is directly proportional to the inertia of the blades ( which is fixed ) and the engine speed (which is variable). The PTO should be energized at an rpm just a little greater than one that won't stall the engine. (often around half throttle). If you know how or have ever driven and straight-shift automobile, it's the same principle. You don't floor the accelerator and release the clutch, you find an rpm balance point that won't stall the engine but will smoothly start the car moving. Now here's a factor you didn't address, stopping the deck blades. The PTO clutch also has a brake which when de-energized, slows and stops the blades quickly. Here again physics come to play, there's less wear & tear on the brake if the PTO clutch is de-energized a low engine rpm. On my Hustler X-One the energize and de-energize throttle positions are indicated next to the throttle by little icons resembling the PTO switch in the correct position. ( i.e. on or off )

[@johnnygogo7773]

I agree with you 100%. My SCAG Liberty Z 36 manual says Not to activate the PTO at full throttle. Thanks for the braking info. I didn't know that.

[@JD0333]

I have also been told everything you pointed out I have no Idea why the manual says otherwise. My Gravely dealer that delivered my mower said the same thing not engage the blades at full throttle to engage at about half and throttle up to full.

[@briandavis7353]

I have owned Cub Cadet, X Mark, and John Deere. Operated Kubota and Bad Boy alot and always engaged with throttle open full

[@thebradleysoncatbirdhill6849]

Hey Brian! Thanks so much. As I had mentioned in the video, all of these commercial guys seem to do it at full throttle. As hard as they push those machines, you would think if that was bad for the machine they wouldn't be using that technique.

[@LumberjackSmokestack]

You are clearly follow the directive. Some forks like to stir up crap just for their own self promotion. Don’t give the the time of day. Keep on a rollin!

[@thebradleysoncatbirdhill6849]

Hey Lumberjack! Thanks so much for your comment. I don't think he meant anything bad about it, he was probably just speaking from what he thought he knew best.

[@copedennis1]

Any mower with electric clutch is the same. Zero turn has nothing to do with it. The belt will last longer with electric clutch

[@patmason7276]

Doesn't matter the belt slips so it absorbs the force. I engage mine almost full for 5 years.

[@crazyadventuresandreviews]

I do lawncare full time and i always engage my blades in lowest throttle. I don’t care what the dealership says, most of the time they don’t even honor warrantees. Don’t listen to these people engage in low throttle I never have any problems a clutch is going to have to be replaced close to a 1000 hours anyways because they don’t build anything worth a crap these days

[@bruceficken6269]

Diesel idle gas full throttle

[@charlieimpala2604]

How did you keep the chute guard up?

[@bernardcaillouet5565]

I own a Toro zero turn and they say engage the PTO at full throttle.

[@eroom2087]

The clutch is designed to last a long time at full throttle and not cause the shaking in the belt drive system, I got a 1996 gt 262 John deer with the same clutch design, never had a problem with pto clutch at full throttle, so the people who designed this machine I would think know what they are talking about

[@tranz15]

My church just purchased a hustler raptor it has a mark at 1/2 throtle to engage the blades my grasshopper i engage the blades at 1/2 also .. but my dads gravley needs 100% or the deck will shake badly at first

[@P_AIR12]

I always engaged at 75% and my belts usually last 1000 hours dealerships will lie to get you bring in the mower for repair that’s there bread and butter lol

[@MySliceOfHeavenoutdoors]

of course I watch this video when Joey isn't here. I will ask him what he does with our ExMark Zero Turn. -Kris

[@thebradleysoncatbirdhill6849]

Thanks Kris!!!!

[@MySliceOfHeavenoutdoors]

@@thebradleysoncatbirdhill6849 different mowers say to do it different ways. I had one mower that said to start the blades at half speed, the one I have now says to engage at full speed. Usually says right at your engage button, if not, check your manual.

[@mikedeiana1504]

There’s so many variations some people say, throttle, half speed, some people say, full speed just go by your owners manual that’s the safest

[@thebradleysoncatbirdhill6849]

Thanks for watching, Mike and also for your comment! It's amazing, I think this is my most popular video ever? I'm still getting comments almost every week.

[@LilShay27]

Day late, dollar short here. My 2021 Scag Z manual says at 3/4 engine speed. I also disengage at 3/4 speed. FWIW.

[@thebradleysoncatbirdhill6849]

Thanks for watching, and your comment! As you can see from other comments, it's all over the board. The general consensus for most manufacturers seems to be full throttle. When I do my next video review of the mower which would be the 100 hour review, I'm gonna try to have an interview with the service tech from Gravely to explain why.

[@LilShay27]

@@thebradleysoncatbirdhill6849 and ask the Tech why there is a difference?? Is it the clutch, belt, deck size that makes a difference?? Also ask testing results and feedback. Just because manufacturers say it, what testing has been performed to prove or disprove. Thanks!

[@KgTV33]

Always engage blades at full throttle. You will damage motor and belts if you don't. It also says in the owner manual. I have same mower and it's like that for any mower. Best to be stopped when you engage blades.

[@medusa210562]

The manual for my scag says about 3 quarters

[@-lawncares5265]

This is normal I own 3

[@johndavis7112]

Full Throttle, or it will throw a belt..... Trust me on that one Gravley ZTXL-42 (2021)

[@racksnquacks8331]

Hello. I’m thinking about buying the same mower. How long have you had it and are you happy with it?

[@johndavis7112]

Love mine it’s a beast with the 24hp kouler engine

[@masterblaster1970]

Absolutely right. It will throw a belt. I took out my PTO connector and had to replace the entire clutch when it threw the belt.

[@howardrobinson8578]

Dealers want you to engage at full throttle so they can sell you more parts.ive ben in lawn care for 22 years and 50 % throttle has worked great.would you full throttle your car or truck every time you take off .comen sence is no.think about it and you will know how to operate your mower.

[@rghong]

Nope… it’s recommended to do it.

[@mikirecords4243]

17 like,sub;-)

[@JamesWilliams-rl2io]

Engage pto at full . Disengage at idle

[@averagejoe8839]

Ive always been told to engage at 3/4 throttle then go to full so as not to burn your belt up. This is what the john deere salesman told me also. Course i would rather burn a belt up than cause extra stress on the engine...

[@thebradleysoncatbirdhill6849]

Check out some of the replies below. You'll see what the mechanic told me regarding engaging at anything less than full throttle. You actually create more belt friction.