3186 vacuum issue
 

I picked up a 3186 a couple months back and recently the PTO stopped engaging. As I was trying to diagnose the problem I found the inner PTO belt (P/N: 954-304) was worn and failed. I replaced the pair, but found the PTO still not engaging. Upon further inspection, I found the vacuum actuator (P/N: 951-3173) is not fully engaging. When I activate the PTO the actuator sucks in just a bit, but not fully. If I give the actuator rod a little help and push it in the mower fires up and runs for a very short time before stopping again. Any ideas where to go from here?

First, welcome to OCC.........:Welcome2:

You have one of two conditions here.
(A) You have not got enough vacuum to engage to the Actuator
(B) Or, there is something wrong with the Actuator itself (worn, broken, leak, etc)

Update:

To test crankcase vacuum with vacuum/pressure gauge:
1. Remove dipstick or oil fill plug/cap.
2. Install adapter into oil fill/dipstick tube opening, upside down over end of a small diameter dipstick tube, or directly into engine if a tube is not used. Insert barbed gauge fitting into hole in stopper.
3. Run engine and observe gauge reading. Analog tester–needle movement to left of 0 is a vacuum, and movement to right indicates a pressure. Digital tester–depress test button on top of tester. Crankcase vacuum should be a minimum of 4 WC in.

If reading is below specification, or if pressure is present, check table below for possible
causes and conclusions.

I believe your actuator is bad. I have had several of these fail with the symptom you have stated and have repaired them. Attached is a link to the failure cause and the way to repair them.

https://www.mytractorforum.com/threa...#post-12433430

ejl6658 - Thank you! It looks like I will have to give this a shot over the next few days.

If you have a "mighty vac" hand vac pump.. You could pull a vacuum on it and see if it actuates and holds properly or does it lose vacuum

I'm with EJL, probably a small hole in the actuator. I had one fail too.