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64gtoguy

Loosing power to my PTO (Sunstar)

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64gtoguy
On my 20 Horse Sunstar, while mowing i loose power to the PTO. The indicator light goes off when the PTO shuts down, and the seat nanny switch is new and works as it should. When I turn the switch off and back on, the PTO will engage and will loose power almost immediatly.This doesn't happen all the time. Some times I can mow the entire yard without a problem and then sometimes the PTO will kick out within just a couple of minutes. I will add that when the problem occurs, the rear PTO is affected as well. Any suggestions ?

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Brettw
Check the clutch adjustment too. Twelve thousandths between the clutch plates, I believe. Not too hard to adjust. There are three "windows" that you can put a feeler gauge into and then tighten the nylock nuts to the proper adjustment. This can cause an issue. When I had trouble, it was the safety interlock module that was causing problems. My issues were a bit different from your however.

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powerking_one
Sounds like you have an intermittent power/ground connection in the PTO clutch circuit (possibly a high resistance point in the circuit that overheats, cools and the clutch works again; the switch itself?). Time to start tracing out, inspect, test w/DVM the wiring, connectors & switch to pinpoint it. Tom (PK)

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Al
HI, These tractors have a complex wiring system, at this time High Tech was the byword. Ariens came out with the HT (Hi Tech) tractors about the same time. Their wiring is a nightmare also. Simplicity saw the advantage to a simple system with the advent of the Legacy. The Sun Star has a number of separate grounds and one of the more common problems is poor grounds. Be sure the interlock module ground is good and as I remember, there are 2 or three more gound spots on the firewall. Sounds like it could be the module. The later and replacement modules have less problems. If you have one of the early modules and get a new one, the plug needs to be turned over to plug in. DO NOT BEND TABS etc to get it to plug in. Al Eden

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64gtoguy
I did an adjustment on the PTO, it was a little wide. Checked the switches. They are OK. Checked the connections, They were OK. Here is what I did discover while tinkering. I can turn the ignition switch on,( with the engine NOT running) I can turn turn the PTO on and it engages and stays engaged. Now,when I start the engine and engage the PTO it looses power almost immediatley. I checked the drive pulleys,idler and mower deck and everything turns freely. Next, I will check all the ground connections, Also does anyone know where I can get an interlock module? I bought one from eBay and it was no good. There is another one for sale on that site but I am a little reluctant to go that route again. Thanks for all the help.

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PhanDad
See Brett's post about similar problem: http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=121652 To see if it's an interlock module issue, temporarily directly ground the clutch (completely disconnect the "-" wire from the clutch that runs to the interlock module, you want it out of the PTO circuit). If the clutch stays energized all the time when the PTO switch is on, then the problem is the interlock module.

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64gtoguy
Thanks for all the help guys, As Bill suggested, I disconnected the ground from the PTO and connected it to the motor block. The front PTO worked first time and stayed on, I mowed for a few minutes before I turned it off and back on. No problem. I will order a new interlock module. Question is, will there be any detramental effects if I use the mower untill the new module arrives?

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PhanDad
Only issue is you lose all the safety features when the clutch ground bypasses the interlock module. The tractor might even start with the clutch (and therefore deck blades) engaged with the interlock module bypassed. So take extra care if operating with the interlock bypassed.

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64gtoguy
I finaly figured out the PTO problem by accident after hours of trial and error. I bought a new interlock module and the problem was still there. So I thought I would give myself a diversion and redo the mower deck. While taking it apart to replace the belt and grease everything I noticed that one of the shaft bearings was a tad bit tighter than the rest. I replaced the bearings and belt put everything back together. And just for the heck of it put the old interlock module back on, started the tractor turned on the PTO and it worked and stayed working, I have mowed the lawn twice and it it still OK. Just thought I would share this. Wierd I know but it appears that too much constant drag causes the module to overheat and kick out. At least it appears that way.

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powerking_one
Sounds like a poor connection (pins/terminals)within the interlock connnector. I would extract the pins (if possible)and inspect/test for high resistance, etc. Tom (PK)

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