bobcat 610 engine wont turn complete revolution

[Yzracer239]

Ive got a 1980? 610 with a wisconsin vh4d engine. I bought the machine last year running but never used due to pillow block bearings in terrible shape. Got all new bearings, driven sheave and shaft, new belt etc., put lots of time and $$$ and finally went to try to start for first time this summer. Other than a few times of a couple seconds or running, so I did hear it. It wouldnt stay running. I was going pretty heavy on the ether, but then gave up figuring id have to pull the carb to inspect and clean. With a week in between, I Did just that, disassembling everything possible, polishing all brass and making new cork gaskets. Put all back together and when tried to start, engine wouldnt turn. starter was engaging but motor was locked. Took my 24" channel locks and grabbed the side of drive sheave, and felt it come unstuck. You can turn the crankshaft as you should with the pliers but it stops solid at the same spot, only allowing most of a revolution?? I took spark plugs out and looked to be a bit of moisture on plugs. I think a bit of water made its way down exhaust over winter, being mostly or entirely responsible for engine not starting before pulling carb. Why wont my motor turn!?? Im scared I might have messed it up with ether, but what and how? Thought maybe timing chain skipped a tooth and valves were hitting piston but its a flat head! Please help!

 

[6brnorma]

Just going by what you are saying.....I would pull all of the plugs and blow each cylinder out with air to eliminate the possibility of hydro lock for starters. Try turning it over with no plugs.
Address the carb once you get it to turn over.

 

[6brnorma]

Just going by what you are saying.....I would pull all of the plugs and blow each cylinder out with air to eliminate the possibility of hydro lock for starters. Try turning it over with no plugs.
Address the carb once you get it to turn over.

Also....the VH4D does not have a 'timing chain'.....all gear driven.

 

[Yzracer239]

Also....the VH4D does not have a 'timing chain'.....all gear driven.

removed plugs was the first thing I did. Still had the same symptom. Im really lost and scared of some major issue when so close to using machine first time.

 

[billrbg]

removed plugs was the first thing I did. Still had the same symptom. Im really lost and scared of some major issue when so close to using machine first time.

If there is any chance water sat in the cylinders for a while, you better pull the heads and see what is going on. If there is rust on the walls or rings you could damage thinks a lot more by trying to force it to turn. Flat-heads are pretty easy to R&R, right?

 

[Yzracer239]

If there is any chance water sat in the cylinders for a while, you better pull the heads and see what is going on. If there is rust on the walls or rings you could damage thinks a lot more by trying to force it to turn. Flat-heads are pretty easy to R&R, right?

like I said, though it sat all winter, I had it running few a few seconds 1 WEEK earlier. How did sitting for a week cause this. Even if some water got in, it should just be stuck, or turn over, not turn over perfectly fine, then feel like it has a stop threaded in a sparkplug hole...im baffled

 

[Bobm500Cat]

like I said, though it sat all winter, I had it running few a few seconds 1 WEEK earlier. How did sitting for a week cause this. Even if some water got in, it should just be stuck, or turn over, not turn over perfectly fine, then feel like it has a stop threaded in a sparkplug hole...im baffled

Sounds like a valve is hung. The same advice applies, remove the heads to inspect so you know whats going on. You may get lucky and remove valve covers. I am not familiar with this engine, but this applies to any engine rust or foreign debris could have come loose and caused a valve to bind. Or since you got ether happy and likely the engine is slightly worn, that ether dissolved oil up into the valve guide and now you have a hung valve. It could break loose with re-lubricating. Worse case, 1 almost full rev means a rod is snapped with the piston holding the rod at the top of the cylinder. Again, This is worse case. Good luck with the repairs.