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Ranwell1, Small Engine Technician
Category: Small Engine
Satisfied Customers: 10304
Experience:  I Own a Lawn Mower Sales and service business (37years). Have 2-cycle and 4-cycle certification.
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I have a 6 year old RZT 50 zero turn mower. The PTO clutch

Customer Question

I have a 6 year old RZT 50 zero turn mower. The PTO clutch has ceased to engage the mower blades. The test light on the control panel indicates the clutch is engaged. How do I determine if the clutch is bad? I was mowing when the blades quit.
Submitted: 5 years ago.
Category: Small Engine
Expert:  James W replied 5 years ago.

James W :

Greetings, My name isXXXXX and I am here to help the best I can. My goal is 100% satisfaction. Let's get started.

James W :

Test to see if the clutch is in fact getting 12 V at the clutch when the Switch is engaged

James W :

You will need a meter

James W :


First. a battery problem will cause major trouble with the PTO. It takes an enormous amount of battery energy to run an electric clutch. So if your battery is low...or goes down, the pto cannot work. Even if there is enough power to start the engine.


If you bought a battery from a discount store. There is a good possibility that either the battery was bad right off the shelf or that it didn't have the required 350 cca that is the minimum for an electric clutch to work correctly for any length of time.


If the battery keeps going down, you could also have a problem with the charging system. Just a note about charging systems in a lawn mower. YOU CANNOT EVER JUMP-START A LAWNMOWER WITH AN AUTOMOBILE OR YOU WILL RUIN THE CHARGING SYSTEM OF THE MOWER. tHE SYSTEM OF THE CAR WILL BLOW THE MOWER'S CHARGING SYSTEM.


You'd have to have the charging system in the mower checked.


The PTO switch could also be bad causing this problem. This happens fairy often.


Also check the wires that attach to the pto clutch. If they came loose, it won't work. Also check for any corrosion on any of the wire terminals and also the battery post and terminals. Also check to make sure that there is not corrosion on the ground cables.


Last but not least, the PTO itself could be bad.... or at least need adjusted...if it has an adjustment. If you have an adjustable clutch, the setting is .010" between the two halves of the clutch...(in between the slots)



James W :

This complete service manual should help you out a bit

James W :

It covers PTO replacment, adjustment, and troubleshooting

Customer: replied 5 years ago.





















i do not believe I have a battery problem. My question was how do I determine if my clutch is bad.

Expert:  Ranwell1 replied 5 years ago.

I am not sure why you opted out James W. He is 100% correct.


You ALways start with checking the battery. A LOAD test is the only way to see if it is good. Even if it is a BRAND NEW battery, It can be bad.


That is the test.. You can test it two different ways.


It is a very strong electro magnet.


So, you can either test everything that I said to test, and if it is none of those, the clutch is bad.


OR, you can bypass all the switches and run jumpers from a STRONG 12V source such as a Car Battery (not running) directly to the clutch + and neg.


You can Hear and See the clutch engage.


If you can not hear it move or see it engage with 12V applied, then it IS bad and needs replaced


And, No one believes that a New battery that is not at least 350 CCA could be the problem.


BUT, we have seen this an average of 3 times per month for 37 years.. I OFTEN is the problem..


In the past, we did not see it so much, because the big box stores did not exist, and you had to buy the batteries at the dealer.


Not saying it is the battery, just saying. Do not discount it. AND do not reply on the existing battery to perform the test.

You also need to check the butt connectors to make sure that you DO have a good connection.


If all else fails, you may end up replacing the Electric clutch or the PTO switch.


If you need any more help with this, you can contact me here at this question...even after you have hit the "ACCEPT" button to pay me for this answer.


Please click "ACCEPT" or I won't get paid.

You may also consider sending a "BONUS" if I have been helpful, Please leave POSITIVE feedback for me as this is how I'm rated. Remember, a neutral is nearly as bad as a negative. If not satisfied, contact me and I will make it right. Thanks


Ranwell1, Small Engine Technician
Category: Small Engine
Satisfied Customers: 10304
Experience: I Own a Lawn Mower Sales and service business (37years). Have 2-cycle and 4-cycle certification.
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