Frozen Intake valve 12.5 hp Kohler

[Cfs]

I am working on a 1987 Ex mark 32 inch walk behind commercial mower. It is a model number 32-12.5kd5. The Koehler engine number is illegible. I can read a Spec of 7275. 390 cc and a serial number 2611504544. Anyway it is a pull start and starter would not pull. I took the starter off and was able to use a ratchet and rotate the engine about a turn and a half and then it will not go any farther. I removed the valve cover and rotated the engine up to where it stops and I was able to observe that the exhaust valve opens and closes, but the intake valve is not opening at all. There was a lot of rust on the push rod for the intake. I have not run into anything like this before I did remove the spark plug and it is not a Hydro lock situation. Do valves ever rust to the valve seats and fuse up? I have seen flywheels rust to coils before and I assume that I need to remove the the rocker arm and attempt to get the valve to move/free it. I suppose that the rocker arm could be rusted to the cam it engages with? This mower has been sitting in a garage for a long time I removed some mouse nesting materials from under the engine shroud...always fun.
Any ideas that anyone can share would be greatly appreciated. I am trying to gather information prior to doing something stupid like forcing the flywheel and maybe breaking something that a little knowledge and patience would have helped me to avoid
Thanks
Chuck
.

 

[Tiger Small Engine]

I am working on a 1987 Ex mark 32 inch walk behind commercial mower. It is a model number 32-12.5kd5. The Koehler engine number is illegible. I can read a Spec of 7275. 390 cc and a serial number 2611504544. Anyway it is a pull start and starter would not pull. I took the starter off and was able to use a ratchet and rotate the engine about a turn and a half and then it will not go any farther. I removed the valve cover and rotated the engine up to where it stops and I was able to observe that the exhaust valve opens and closes, but the intake valve is not opening at all. There was a lot of rust on the push rod for the intake. I have not run into anything like this before I did remove the spark plug and it is not a Hydro lock situation. Do valves ever rust to the valve seats and fuse up? I have seen flywheels rust to coils before and I assume that I need to remove the the rocker arm and attempt to get the valve to move/free it. I suppose that the rocker arm could be rusted to the cam it engages with? This mower has been sitting in a garage for a long time I removed some mouse nesting materials from under the engine shroud...always fun.
Any ideas that anyone can share would be greatly appreciated. I am trying to gather information prior to doing something stupid like forcing the flywheel and maybe breaking something that a little knowledge and patience would have helped me to avoid
Thanks
Chuck
.

Push on the valve spring and spraying with penetrating fluid. Remove cylinder head if necessary.

 

[Cfs]

I am thinking that I will have to pull the cylinder head. I will try pushing on the valve first. I am wondering if the valve sear on the intake valve came looseand has the valve jammed in the open position. If it is that...can I use the same procedure I have done on a few Briggs engines of getting the seat in place and using a punch make a series of dimples around the seat to create a ridge to hold the seat in? I am a new comer to OHV heads and issues with them and a complete novice on Kohler. I will look at it later this morning after the rain stops. I down loaded a Kohler service manual from a link on this site. I think it to be correct..looks like it is a Koehler Command vertical 12.5 in hp. Not sure if there is another Kohler engine series that has a12.5 hp size. A lot of the photos look accurate to what I am seeing

Thanks for any and all input

Chuck