Stuck yanmar 165D

   / Stuck yanmar 165D #1  


Bronze Member
Jun 17, 2024
yanmar 165D
Been lurking on here for a bit and have learned a bunch. I have a yanmar 165D with 290 hours on it that has been sitting for the last 7 to 10 years in a machine shed. I am in the process of buying from my neighbor and it is actually now sitting at my house. Not able to get it started as I think the rings are stuck to cylinder walls. I attempted to take injectors out, but they have never been removed before and despite my best efforts those wouldn't budge. So, I prepped to take the head off. Under the valve cover, is absolutely spotless. No signs of water (exhaust was in horizontal position). When I took the head off, cylinder walls look perfect and no signs of water either. I filled both cylinders full of 50/50 ATF and xylene. Question is, how long should I let it sit before giving serious effort to try and spin the motor? I go out every morning and put a little pressure on the PTO with a pipe wrench. Thanks!
   / Stuck yanmar 165D #2  
Have you tried a socket on the crankshaft pulley? I think you would get more torque on the engine. I know it may not be easy to access.
   / Stuck yanmar 165D
  • Thread Starter
Yes I have
   / Stuck yanmar 165D #4  
Yes I have
First be sure everything is in neutral then I would lock the clutch pedal down with the lock down tab on the footrest. If it is missing put a 2x4 between the footrest and the clutch pedal arm to hold it down. This will avoid trying to turn the driveshaft and tranny.
Next there is a rubber plug in the left side of the clutch housing that when removed exposes the ring gear and the side of the pressure plate.
With a heavy screw driver you can try to turn the ring gear. This requires much less torque than turning crankshaft or PTO.
If the clutch plate is stuck to the flywheel or to the pressure plate after sitting for so long it can be freed up thru this access hole by lining up a side opening in the pressure plate and pushing a small long handle screwdriver in between the clutch disc and the pp and the fw.
   / Stuck yanmar 165D #5  
Last yr. the F2000 clutch was stuck found that out when I finally got it to the house. 2 stage and the shop showed me the old clutch pack. Pry Bar through the starter no doubt. So be careful! While it's down and make sure to catch and go through it all.
If it not the Trans. locking it up. I would be planning on pulling the Oil pan and Crank shaft and get the stuck piston/pistons out. May not be all Stuck?
   / Stuck yanmar 165D
  • Thread Starter
Thanks all. I'm going to keep letting it soak then I will try the access hole. I don't want to put too much pressure on it yet without a real good soak. Not quite a week yet and I'm not seeing any signs of this fluid in the oil
   / Stuck yanmar 165D #7  
Thanks all. I'm going to keep letting it soak then I will try the access hole. I don't want to put too much pressure on it yet without a real good soak. Not quite a week yet and I'm not seeing any signs of this fluid in the oil
Have you thought about using a rubber mallet to only tap the pistons a little after a bit of soak time? I'm not suggesting heavy blows either. Just some TLC nudging.

I only helped a person free their engine rings before. We used Seafoam as it's a thin based fluid. And it states to free rings and lifters too. Did this on a VW long ago. It worked to our surprise on that diesel. AFT is a bit thicker. Xylene is more of a stripper.
If the xylene floats on top of the ATF, then nothing is going to happen anytime soon. With a plastic item, you could stir it from time-to-time.

   / Stuck yanmar 165D #8  
Auto Trans fluid is what seems to work the best! Everybody has Done it for decades!!
   / Stuck yanmar 165D
  • Thread Starter
I used the xylene to thin the ATF as I read that xylene works better than acetone and I had some on hand. I will give it a few weeks and if I can't get any rotation on pto or don't see any evidence of the mixture in the oil, then I will pull the head and start tapping or maybe put diesel in the cylinders and let that soak in
   / Stuck yanmar 165D #10  
Xylene/ATF is a good approximation for SeaFoam in unsticking rings in my view. I tend to use SeaFoam more often, but that is purely a personal choice. I've only done it a handful of times.

@millard762 From your description, I would have been leaning towards a frozen clutch as a starting point, but since you have moved the tractor from your neighbor's shed to yours, I'm guessing the clutch works. Right? Assuming that the clutch works, if it were me, I would follow @Gjamtrac's advice to block the clutch open, and use a screwdriver, and / or @bmaverick's advice to use a rubber mallet or a block of wood to tap each piston with the clutch open. You won't be putting stress on the rest of the transmission, and you can readily get a lot of leverage.

In my experience, it is unusual for an engine that looks pristine inside not to move freely after an overnight soak in ATF/seafoam. Have you drained the engine oil from the pan and looked for debris there, with and without a magnet?

All the best,