It’s a good idea to check the engine speed of any new mower. There are occasions when the mower’s engine speed is not set to the manufacturers specifications. You can have the dealer verify the full throttle RPMs before taking delivery.
Check Your New Mowers
- Thread starter MParr
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I assumed that my Gravely dealer checked the low idle RPMs and no load WOT RPMs before I took delivery. I specifically told them I wanted it checked before my purchase. I sensed that it wasn’t set right. I finally got around to checking it. Sure enough, WOT was below 3,400 RPM at no load. I pulled part of the rear bumper off to get at the linkage. It is now set to the Kohler specifications outlined in the ZT740 service manual. It’s dead on 3,600 at WOT and 1,450 with the Governor linkage away from the carburetor. It’s running really good.
Tiger Small Engine
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Idle is usually 1850 RPMs and on newer (less than 10 years), often around 3250 wide open throttle. Maximum RPM for small engines is 3600.
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Just because the service manual says 3600 rpm doesn't mean that your particular was spec'd to be set at that speed. Here I look up the engine per their spec numbers on the Kohler's dealer website.
And setting the speed the engine's spec can cause other problems as the equipment manufacture was keeping things within the max rpm limit for the hydros and the deck blade tip speed. Running the hydros above their safe rpm can lead to early failure just like running a sustain minimum speed.
Examples of a few of KT740s is
And setting the speed the engine's spec can cause other problems as the equipment manufacture was keeping things within the max rpm limit for the hydros and the deck blade tip speed. Running the hydros above their safe rpm can lead to early failure just like running a sustain minimum speed.
Examples of a few of KT740s is
Before I made the adjustment, I contacted Ariens customer service to confirm.
The idle speed is set exactly as the same as the KT740. This idle speed was noted in the ZT740 service manual. It could have something to do with the engine application. The KT740 is usually mounted on residential units with residential hydrostatic transaxles. I have Hydo-Gear ZT5400s in my unit. The engine on my Gravely is a ZT740-3046.
The idle speed is set exactly as the same as the KT740. This idle speed was noted in the ZT740 service manual. It could have something to do with the engine application. The KT740 is usually mounted on residential units with residential hydrostatic transaxles. I have Hydo-Gear ZT5400s in my unit. The engine on my Gravely is a ZT740-3046.
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When I do a PDI on a new mower I always Check the top no load speed, idle speed. Along with all the other things I check. Loose Hydro bolts, lug nuts, engine mounting bolts, tire pressure, engine oil, seat bolts and various other things. Good to go and don't come back.
I asked my Gravely dealer specifically to check the no load full throttle and idle speed. I don’t think it was done. I suspected the WOT speed was low. I have some Common Bermuda Grass over my septic drain field. It’s really thick and I’ve noticed the engine wasn’t performing as it should. When cut, the grass had a burned look to it. The engine did fine on the rest of the yard. My neighbor has a Bad Boy Maverick with the same engine and his unit is screaming. My ears told me that he was turning more RPMs at WOT. The landscaper who cuts the property next door runs Exmarks with Kawasaki engines. Their engines sounded to be running faster at WOT.
Every dealer should do as you do on PDIs.
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For your particular spec you set it right. Just like to check things before I type specs. Just too variables to remember off the top of things. I rather look bad by posting the right info then post bad info.
Thanks @StarTech!
I wouldn’t think that Gravely would set the WOT RPMs any different on the Kohler ZT740 than the Kawasaki FX850V. The blade tip speeds should match across the Pro Turn 260 models.
The engine may have been set to the 7000 series specifications before it left the Kohler factory.
Or, it was set wrong somewhere along the line. Anyway, it’s dead on now.
Again, thank you so much for the confirmation.
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