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Small Engines (Lawn Mowers, etc.)/Kohler 27 HP - Toro zero turn - vibration


I have a 62" Toro commerical zerto turn mower, which has developed a vibration / grinding like noise from the forward output shaft area.  If I take the hyraulics belt off, the noise goes away.  I have checked everything related to the hydraulics, pumps, idler pulley, you name it, nothing seems out of place, or bad.  

This engine has a bolt on flanged front output shaft.  I pulled the rotating brush cover off this, and checked it thinking a bolt might have broken, nothing wrong there.  

Could the stress of the belt being on the motor shaft somehow strain the front bearing on the motor enough to make this noise, yet, when the belt is off, it could run quiet ?

One other thing, I started using non-ethanol fuel just before this started. I doubt this is the issue, but just asking if a better fuel could create this noise in the motor somehow?

Service shop is out two weeks, and I don't want to tear it up cutting, but the grass is growing fast.



The stress of the belt could cause the noise but the engine would have to be really, really wore for this to happen.

Are the engine mounting bolts tight?  I would check all the bolts, nuts, screws in the affected area as I have often found loose fasteners cause noise, vibrating and even no shift/difficult to shift trans problems.

How work is the belt?  A oddly wore belt can also cause vibration.


Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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