Craftsman PTO Switch Burn Out

12 years ago

Hello, I have a Craftman DYT4000 Lawn Tractor model #917.275700 (I bought it brand new in 2005)(only used for home use on 3 acres of land)(garage kept). I am having issues with the PTO switch (part #174652) . I have replaced this switch 4 times and it continues to burn out each time (top of switch comes right off in my hand, can see melted plastic on end of top and inside). The first switch lasted for 4 years, the 2nd switch lasted over a year, and the last 2 lasted less than one month. I currently have 2 new switches on order and I know I will continue to burn out the switches unless I can find the electrical problem causing it. After reading other forums I looked for any frayed or shorted wires (found none) I looked for corosion on any of the cables (found none). Checked the 20 amp fuse (looked ok). Could it be the electronic clutch or hopefully something a lot less expensive. Sears wants $101.00 to send someone out just to look at it.Could anyone please give me some advice on the next step to take. My grass is already up to my knees and I would love to just get back to work and cut it. Thank You

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Comments (3)

briggsgalaxieman
12 years ago
I can think of two possible causes of burning out the PTO switch that quickly (#2 is most likely the cause):

1. The PTO is drawing way too much current. Disconnect the PTO coil and measure its resistance. The PTO coil should be about 4 ohms.

2. Look at the schematic in your owners manual. There will be a diode connected in parallel with the PTO coil. The job of that diode is to protect the switch from arching when the PTO is switched OFF. If that diode is defective or disconnected the PTO switch will burn out after a short number of uses. Find that diode and check to see that it is OK. I am not sure where the doide is located on your tractor, but maybe when you installed the first replacement switch the diode did not get reconnected properly.
bill_kapaun
12 years ago
According to the schematic, the diode is "hardwired" to the clutch (or integral)

Resistance of the clutch winding should be ABOUT 2.6 OHMS to 4ish.

Any less means it will draw too much current.
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User
12 years ago
Bill,

We've been here before... the diode is not hardwired internally in the PTO. The schematics are more electrical diagrams that actual schematics.

See this thread... http://forums2.gardenweb.com/forums/load/tractor/msg0519392515490.html

There's also a link in that thread to a troubleshooting guide for electric clutches.