PTO & Clutch issues, Help

[horses2]

Working on a Sears Craftsman model 917272021 16.5 hp tractor. Unit was running fine and then cut off while the wife was using. (Yea, I know but lets try to stay on track here :laughing:)
Tractor starts and engine runs fine. When PTO is engaged, and/or clutch engaged, the engine cuts off. I checked the seat switch and it is working correctly (ohm test & jumper wire) and does not seem to affect the tractor operation. whether open or closed the tractor will die when engaging the clutch or PTO. Also the ammeter reads full charging (15amps) when at full throttle. Battery seems to be fine as it spins the motor and fires the engine very quickly. I switched the operator sensor circuit relay with a Bosch unit from a fog lamp set I had and now with the switch disengaged (up or open) the unit will run with clutch engaged (tractor moves) but engaging PTO will cause unit to die. if I hold the switch closed, the tractor will die when the clutch or PTO is engaged. Also with the new relay the charging rate is back to normal. Any thoughts or suggestions?

Thanks,

 

[J_J]

Do you hear the clutch click on? Does the clutch turn at all when the switch is engaged. Do the blades and pulleys turn freely?

From what you say, the blades and or pulleys are locked up. Maybe a wire or string is wrapped around a shaft. or a pulleys has welded itself to gather.

 

[horses2]

no click when PTO engaged. The clutch does not turn at all when switch engaged. The engine acts like spark has been cut off when engaging PTO and or clutch. Pulleys and blades turn freely.
Same symptoms exist when connector at PTO clutch disconnected. Voltage to PTO clutch is less than one volt when engaged.
I am wondering if the PTO switch or clutch switch has failed, as the tractor acts like there is never anyone in the seat, ie the safety circuit kills the engine spark when clutch or PTO is used.

Thanks,

 

[J_J]

To check the clutch only, unplug the wiring connector to the clutch, and apply 12v directly to the red or positive wire to clutch, make sure you have a ground. Your clutch switch could be shorting out and killing the engine.

Go directly to the switch and see if you have 12v at the switch.

Bypass the switch momentary to see if the clutch will engage when you apply voltage to the clutch wires.

 

[J_J]

What is the ammeter doing as you flip the clutch switch?

 

[jgrinn]

Maybe a coil is going bad. Had the same problem with a cub cadet last year, it was the coil. Only did it when I engaged the pto. Also, take the belt off of the pto to the deck and try it again, that will at least eliminate something with the deck.

 

[horses2]

ammeter doesnt change (shows full 15a charging) when activating the PTO switch, I disconnected the leads to the PTO clutch and the issues remain the same. When the engine dies, it seems that the spark is being cut as the engine will backfire out the exhaust. The mower deck spins freely as does the PTO clutch (disengaged)

 

[rodneyhd]

I have acraftsman model 917.272021 that is doing the same thing. where can I find a wiring sechematic for this tractor. help is needed.

 

[J_J]

If everything works good except the PTO, then either the switch is shorting out, or the wiring from the switch to the electric clutch is shorting out somewhere. The clutch itself could be shorted out. Read the ohms across the clutch and see what you have.

Try applying external 12v to the clutch.

 

[horses2]

The PTO will activate when 12v is applied. I removed the wiring harness and no apparent shorts chafs, or bare spots. I did change the ignition switch (wondered how the insides worked, and well....), symtoms remained the same. Since the harness appears to be intact, I am going to replace the PTO switch as all the circuits seem to run thru it,
I have a wiring diagram from the Sears, but it doesnt help, its too simple and doesnt show enough detail.