M valve stuck

Hey everybody, new development on the M Im trying to free. I dont have anywhere to get it in, so Im doing things in tractor and trying not to have to pull the head. Ive discovered one of the valves is stuck down, the rest work, any ideas on how to free it?
Thanks
 
Exhaust or intake can make a big difference. If exhaust pour ATF down the exhaust pipe so as to fill that cylinder to the point the whole valve it covered. Let it sit a few days. Then if you can grab the end of the valve with vise grips and turn and pull up on it. I have free up more then one that way. The just keep working it up and down till it has freed up all the way. If intake well you fill the cylinder up with ATF then if the engine is free turn it over till you get some ATS out of the carb then stop let sock then turn it a bit more in 24 hours so as to keep it coated. Then do the vise grip thing
 
My first choice is to remove the pushrod and wire the rocker to one side. Then I lube the stem through the spring with a tube nozzle. next I use a big screw driver and a plastic faced hammer to tap down on the valve butt (small taps, not to drive it down) then pry up under the spring top coils (again gently) repeating this for as long as I can stand it, or trying again the next day. Do not pry to bend the stem!! Jim
 
One way to test if it is exhaust or intake is pour ATF down the exhaust pipe with that plug out. If you start getting ATF out the plug hole well you know it is exhaust. If that does not work fill the cylinder with ATF and if you get ATF out the carb it is intake. Ya I could look and know but then I have messed with engines 40 plus years now
 
Exhaust-Intake-Intake-Exhaust-Exhaust-Intake-Intake-Exhaust from front of tractor to rear. (Tapping on it is easy and makes less smoke). Jim
 
I had one on a 504 stick,I oiled the stem and fed a piece of 1/4 rope in the spark plug hole. I rocked the crank shaft back and forth for a couple of days and it came up.(the piston would hit the valve but the rope gives it some cushion.)
 
(quoted from post at 15:42:14 01/11/15) Hey everybody, new development on the M Im trying to free. I dont have anywhere to get it in, so Im doing things in tractor and trying not to have to pull the head. Ive discovered one of the valves is stuck down, the rest work, any ideas on how to free it?
Thanks

Spray some blaster on the valve stem and tap it with a small hammer a couple of times. Unless it is totally rusted the spring will push it up.
 
thanks neat idea, I was thinking it was hitting the valve, thanks for confirming, I hit the stem with blaster and walked away for a day or two, hope it works! Thanks
 
(quoted from post at 10:42:24 01/12/15) thanks neat idea, I was thinking it was hitting the valve, thanks for confirming, I hit the stem with blaster and walked away for a day or two, hope it works! Thanks

Be sure to tap it with a hammer a bit. If it frees up then keep repeating the procedure. I have had tractors stuck because of valves hanging up..
 

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