Repairs PTO not working after 30+ minutes run time

[Dmrboss]

Hello-
I have a Cub Cadet riding lawn mower (model 1515, purchased in 2002- serial 1B072H20225) and the PTO is not functioning properly. It will run fine for 30-40 minutes (start, stop, reverse, etc) then suddenly stop engaging. I have to turn the mower off for 30 minutes or more and let it cool down. When I restart mower the PTO will work again. Anyone have an idea what might be causing this and how to diagnose the problem?

Thanks in advance!

 

[reddragon]

sounds like electrical....like defective safety switches or bad pto clutch....if a switch case is broken....it can swell with heat pulling the contacts apart.....then cools and comes back together ....something is shutting your PTO clutch off....check your safety switches for anything obviously wrong....heres a set of diagrams that might help....http://www.partstree.com/parts/?lc=cub_cadet&mn=1515 ...can you take pictures for us?..............do you know how to use the continuity setting on a multimeter?

 

[djrussell]

looks like you forgot to link something there, RD.

 

[Dmrboss]

sounds like electrical....like defective safety switches or bad pto clutch....if a switch case is broken....it can swell with heat pulling the contacts apart.....then cools and comes back together ....something is shutting your PTO clutch off....check your safety switches for anything obviously wrong....heres a set of diagrams that might help.....can you take pictures for us?..............do you know how to use the continuity setting on a multimeter?

I have a multimeter and can check continuity.

 

[reddragon]

oops!...it should work now:tongue:

 

[olf20]

Most likely it's the coil in the clutch. We have seen this many times.
The easiest way to check this is to unplug the clutch and put
jumper wires to the battery. Leave on for a length of time to see if
it drops out.
The problem with a meter is that it is hard to catch the coil opening
up. If you are standing there when the clutch drops out, you should be
able to check the continuity immediately after the clutch drops out.

Also if this is a adjustable clutch ( three nuts on bottom) you need to make
sure that it is adjusted properly. A gap this is too big with draw too much
current, over heat the clutch coil and cause the problem you are having.
Of course there are other causes for this but the above check eliminates
everything except the clutch.
Hope this helps!!
olf20 / Bob
Oregon Lawn & Farm

 

[Dmrboss]

Hey Bob,
Thanks for the suggestions. It is an adjustable clutch so I'll check the gap first then jumper directly to the battery to see if coil is the problem.