snapper zero turn clutch testing

M

Mark H_NO

Well-Known Member
I've been working on a snapper scrambler 33" zero turn. We mowed with it today for over an hour, then the blade disengaged, and won't engage. I am told the switch has been replaced a couple times in the last year. I'm headed there tomorrow to pull and test the switch, and test the clutch. I read in a thread here that you can turn on the ignition and engage the blade switch and should get 12 V on the connector to the clutch. Will it do that without running? I was thinking that some safety circuit would block it...

If I put 12V direct to the clutch, can you feel it engage? I would think you'd be able to tell by turning the blades...

Model SZT183368bve

Thanks.
 
While sitting on the seat, turn on the igniton switch and pull the pto button, and you should hear the clutch engage with a load click. Also applying 12 volts to the clutch wires will also engage the clutch.
 
If the switch has already been replaced several times it is possible the electric clutch is partially shorted. These switches are designed for 5-7 amp continuous current draw and a partially shorted PTO field winding can pull up to 20 amps and still work. Test the PTO field winding with an OHMS meter and the resistance should be 1.7 or higher OHMS.

Also check for bad wire terminals at the switch they also can cause the switch to overheat.

And please verify your model number as I am not finding on the Briggs Power Portal.
 
Some have spaces or dashes like SZT-183368-bve. That is the model number from the sticker. I did pull it up on briggs site, looking for part number for the PTO switch.

Thanks for the info.
 
Mark H_NO said:
Some have spaces or dashes like SZT-183368-bve. That is the model number from the sticker. I did pull it up on briggs site, looking for part number for the PTO switch.

Thanks for the info.
Click to expand...
Test the connections before you order a clutch. You want to confirm that there are no loose connections, broken, or places the wiring is chuffed and grounding out. You can test the clutch independently using a 12 volt battery.
 
1776341166964.png
Ahhh one digit too many. SZT18336BVE.

PTO switch 7075884YP [Delta 6201-219] Yellow Knob with Black graphics.
1776342600620.png
Common PTO can be replace a Red knob or even a Black knob version as long the pin out is correct.
1776342724321.png
 
Electric PTO clutches often wear the steel plate faces and the air gap increases with age and use. Some clutches have 3 noticeable studs with nuts that are adjustable to reduce the air gap. On those, a 1/4 of a turn equally on each nut will suffice to close the gap and eliminate the problem.

If the PTO clutch does not have the adjustment capability, it may need to be replaced.

Before considering that option, disconnect and reconnect every connector you can find on the machine to reseat them. Often times this will correct mystery problems like you described.

Be sure to check the PTO switch connector for spread female pins due to overheating in the past. Spread pins will lose contact intermittently. Seeing how the switch has been replaced multiple times, this is a real possibility. It is easy to assume the pins are tight.
 
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