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Old 09-10-2011, 12:08 AM
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soloscaperman soloscaperman is offline
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Anyone run your ZTR's at a hair under Full throttle

Wondering if the gas savings is worth it. My mower is loud and when mowing it at 90%-99% throttle it stills cuts the same and it's very quiet. I have a 27HP Kohler on a 2008 Exmark Lazer HP ZTR combined with a little 52 deck so it still has power. I do hear the Hydro's more so is it stressing them out????
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Old 09-10-2011, 12:22 AM
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MCFISH MCFISH is offline
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Great question. I will be following this thread, to see what others have to say. I run mine wide open 100 %. I don't think my machine would work well at reduced power. I'm sure people with different machines will have some insights on how they have been able to save fuel at lower power setting and still give a good cut.
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Old 09-10-2011, 12:42 AM
Ridin' Green Ridin' Green is offline
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Here are a couple things to consider.

1- Manufacturer's design the spindle pulley size, pto pulley size and the blades for each machine to give optimum performance when run at full throttle on that particular machine (or range of machines within a certain class) with the particluar engine size used. WOT throttle is not the same as wide open, since all engines have some type of governor on them. That means they are actually more fuel efficient when run at WOT in normal mowing conditions

2- My dad always ran any of his tractors he mowed with at about 3/4 of WOT. I kept telling him the above info, but having come up through the depression, he was bent on saving anywhere he could. I finally proved it to him one day. He mowed his 2.5 acres with his garden tractor (which was only a couple years old, and this was only a couple years ago) at his normal setting of 3/4 throttle. A few days later (this was during the spring peak growth season) I mowed it again when the grass was at a length that was close as possible to the same length as when he mowed it. I used WOT. He went through 2 full gallons. I went through 1 3/4 or a bit less gallons. We repeated the test a couple more times with identical results, and after that, he didn't argue anymore (but he still would only go to appr 7/8 of WOT because after all those years of believeing that way, it still seemed to him like it should be saving him money).

3- most machines use an electric PTO, though not all as some have a hydraulic pto clutch. Those with electric pto's need the engine to run at WOT to make sure the battery is being charged correctly while at the same time providing enough current to provide the correct current to the engine, and the electric PTO clutch.
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Old 09-10-2011, 01:08 AM
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soloscaperman soloscaperman is offline
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Quote:
Originally Posted by Ridin' Green View Post
Here are a couple things to consider.

1- Manufacturer's design the spindle pulley size, pto pulley size and the blades for each machine to give optimum performance when run at full throttle on that particular machine (or range of machines within a certain class) with the particluar engine size used. WOT throttle is not the same as wide open, since all engines have some type of governor on them. That means they are actually more fuel efficient when run at WOT in normal mowing conditions

2- My dad always ran any of his tractors he mowed with at about 3/4 of WOT. I kept telling him the above info, but having come up through the depression, he was bent on saving anywhere he could. I finally proved it to him one day. He mowed his 2.5 acres with his garden tractor (which was only a couple years old, and this was only a couple years ago) at his normal setting of 3/4 throttle. A few days later (this was during the spring peak growth season) I mowed it again when the grass was at a length that was close as possible to the same length as when he mowed it. I used WOT. He went through 2 full gallons. I went through 1 3/4 or a bit less gallons. We repeated the test a couple more times with identical results, and after that, he didn't argue anymore (but he still would only go to appr 7/8 of WOT because after all those years of believeing that way, it still seemed to him like it should be saving him money).

3- most machines use an electric PTO, though not all as some have a hydraulic pto clutch. Those with electric pto's need the engine to run at WOT to make sure the battery is being charged correctly while at the same time providing enough current to provide the correct current to the engine, and the electric PTO clutch.




That answers my question if it was 1/2 throttle but I am talking about moving the throttle a hair. Cutting is still good but the hydro's act totally different meaning a little noisy and jerky if I drop the throttle a smidge. Kohler 27HP engines have very good low end torque.
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"Money & Power leads to Greed and usually ends with Corruption."

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" A LEADER will always have more haters than a FOLLOWER."
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Old 09-10-2011, 01:21 AM
Ridin' Green Ridin' Green is offline
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Sorry, I meant to address the hydros too. It's been my experience that they do perform better when run at WOT. I am guessing that having the pulleys that drive the pumps turning at optimum rpm's has a direct affect on how they (hydro's) perform when a demand is made on them, like turning, stopping/starting, going up hill, etc.

I know I can always tell a difference on my hydro tractors too when they have any sort of load on them, even my compact utility tractor. It's simply fluid dynamics. More fluid being pumped through a device equals more/easier performance capability.

Also, if you re-read that post above, we weren't comparing the gas used at 1/2 throttle vs full throttle. He was using 3/4 or a tad more, while I used full. Even when he went to 7/8 throttle, I still got better fuel econmy at WOT than him.

The part about the PTO came from a friend of mine that owned a dealership. He told me that that was why the manufacturer always put that into the owners manual, and applied to anytime an attachment was run off the pto. It is one reason that many people have to replace their batteries more often than would be expected. They simply don't get charged properly, and eventually they go bad.

Last edited by Ridin' Green; 09-10-2011 at 01:28 AM.
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Old 09-10-2011, 08:56 AM
Tim White Tim White is offline
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My Tank has a 30hp kohler and wide open rpm is 3450. I have always run it @ 3200 and that seems to be the sweet spot, not sure about fuel savings but still running the original battery. I run all my equipment this way and they hold up for a long time. Just my 2 cents.
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Old 09-10-2011, 12:02 PM
MS_SURVEYOR MS_SURVEYOR is offline
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Quote:
Originally Posted by Tim White View Post
My Tank has a 30hp kohler and wide open rpm is 3450. I have always run it @ 3200 and that seems to be the sweet spot, not sure about fuel savings but still running the original battery. I run all my equipment this way and they hold up for a long time. Just my 2 cents.


I too have a 30hp Kohler. I was looking for info on the Kohler site and found that the 30hp Kohler is factory set at 3750 rpm, no load. Talked to a Kohler engineer and he was very point blank about sending out the 30 hp from the factory at 3750 rpm.

That being said, I run mine wot with load at 3640. Cutting grass at 3560 to 3480 rpm. I burn about 1.4 gph. Thirsty son of a gun! Wish I had a 28 efi!
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Old 09-10-2011, 03:11 PM
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Richard Martin Richard Martin is offline
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Quote:
Originally Posted by MS_SURVEYOR View Post
That being said, I run mine wot with load at 3640. Cutting grass at 3560 to 3480 rpm. I burn about 1.4 gph. Thirsty son of a gun! Wish I had a 28 efi!
There would be no point in the 28 EFI if you're trying to save gas. My 28 EFI burns an average of 1.3 GPH.
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Old 09-10-2011, 03:26 PM
StanWilhite StanWilhite is online now
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Quote:
Originally Posted by soloscaperman View Post
Wondering if the gas savings is worth it. My mower is loud and when mowing it at 90%-99% throttle it stills cuts the same and it's very quiet. I have a 27HP Kohler on a 2008 Exmark Lazer HP ZTR combined with a little 52 deck so it still has power. I do hear the Hydro's more so is it stressing them out????
On level ground I use only the throttle necessary for the height and thickness of the grass I'm cutting. No need in making more noise, burning more gas, and creating more dust than necessary.
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Old 09-10-2011, 05:17 PM
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Pennington Lawncare Pennington Lawncare is online now
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A quick read through your owners manual will probably clear this up and any I have ever read said to run them at full throttle and the main reason is the blade tip speed is reduced when the engine is not run at full throttle.
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