ZD331 Engine Issue

[2Huskies]

Hello. I'm looking for some help with an issue I'm having with my ZD331 (D1305 diesel engine). The mower was running fine the last time I had it out in early August, but it hasn't gotten a lot of use this year due to a lack of rain. I went to try and start it last week and the starter was just clicking. Got it to turn over, but it didn't seem to be turning over well and it didn't seem to be trying to fire. I figured maybe the battery just needed a charge, so I stopped cranking it to charge the battery. While the battery was charging, I pulled and disassembled the starter so I could chuck the rotor up in the lathe to clean up the armature. Didn't turn any material off, just used some fine sanding cloth while spinning to clean the copper up. Reassembled, tested and put it back in the mower and tried to start it. Engine turned over a little bit and then just stopped turning. Tried turning the flywheel by hand the opposite direction. Flywheel will spin roughly half a revolution and then it stops and refuses to move any further. Turning it back the other direction, it spins roughly half a revolution and then stops and refuses to move any further. Moderate effort trying to turn it did not make it spin, so I stopped and didn't try to make it turn further.

Things I have tried so far that have not resolved the issue:

1. Pulled glow plugs in case it was somehow hydrolocked.
2. Disconnected drive shaft to hydraulic pump in case the hydraulic pump wasn't turning.
3. Pulled fuel injector pump assembly in case something in there was seized up.
4. Pulled valve cover to check valve train. All appeared okay, so pulled rocker arm assembly in case a valve was somehow stuck, still no go.


Is there anything else I should check before just pulling the engine and starting to tear it down to find the issue? Any place in particular to look first if I have to start tearing down the engine? I don't want to tear it down any further than necessary.

The engine has 395 hours on it.

At this point in the season, this will likely be added to my list of winter projects.
Thanks in advance for any help!

 

[whitetiger]

Take a 22 mm socket and ratchet, try turning the engine over using the bolt retaining the front pulley onto the crankshaft.

 

[Anil8tor]

I'd double check that the PTO is disengaged. Then put a pipe wrench on the PTO to make sure it spins freely. Also make sure you are in neutral and see if you can roll it. I had a Satoh 550g that did the same thing, turns out it was the transmission not the engine. Of course you sound pretty competent and have probably tried these things already.

 

[2Huskies]

Take a 22 mm socket and ratchet, try turning the engine over using the bolt retaining the front pulley onto the crankshaft.

I did put a socket and breaker bar on the crankshaft pulley today, but no luck. Engine still only turns about half of a revolution either way and then hard stop.

 

[2Huskies]

I'd double check that the PTO is disengaged. Then put a pipe wrench on the PTO to make sure it spins freely. Also make sure you are in neutral and see if you can roll it. I had a Satoh 550g that did the same thing, turns out it was the transmission not the engine. Of course you sound pretty competent and have probably tried these things already.

I had thought that it could possibly be the hydraulic pump/transmission, which is what runs most everything on the mower, but I disconnected the pump driveshaft to eliminate that as a potential issue. I was certainly hoping it wasn't in the hydraulics, since I bought it with a bad transmission and rebuilt it a couple years ago.

I do appreciate the suggestions, though, as I'm about out of ideas short of tearing into the engine. Thank you!