Stuck exhaust valve

[Schu]

Getting near the end of a winter mostly cosmetic restoration. This Cub always ran very well. A few days ago while tuning and installing a new governor spring, it stopped running well. After a bunch of diagnostic work I found the problem. #2 exhaust valve stuck open. Before I start anything drastic I thought it best to ask for advice on the best way approach freeing it up. Hope I can do so without pulling the head.

[SamsFarm]

Me personally, I would probably try to push it up and see if the extra spring tension pops it back down.

Maybe lube the stem first too!

[Schu]

Tried that. No go.
It seems that the valve head is a little bit under the spark plug hole. I am thinking a bolt the size of the spark plug may push it down. I squirted some PB onto the top best I could

[Barnyard]

I have used a small brass drift and put it in the spark plug hole and lightly tapped it with a small/medium sized hammer and gotten them loose. If you use anything hard, such as a bolt or screwdriver you need to be careful not to damage the valve.

[Don McCombs]

A wooden dowel would work, too.

[Nosparkplug]

Why would a valve just all of a sudden get stuck? This is what I was thinking about when I asked about lead in gas. What other lubrication do valve stems and guides get besides splash from the bottom? What say ye Cub gurus. Tap REAL GENTLY!

[Glen]

You can pull down on the bottom part of the valve below the spring, sometimes they are not very tight in the valve guide.
When it goes down, lube the lower part of the valve stem too, and work it up and down many times.
Be sure it closes each time before putting the cover on the side of the engine.

[staninlowerAL]

Getting some lubrication under the head of the open valve to lube the stem can be done through the spark plug hole using a soda straw extension and some spray lubricant like PB blaster. Stan

[Schu]

Thanks for the tips. I will go to work on freeing this up. Looks like no magic solution.

I also wonder about root cause. It seems stuck valves are not unknown for these engines.
I am using Shell Rotella T4 15-40 oil. Now thinking some 2 stroke oil added to the gas might be a good idea.

[Eugene]

I also wonder about root cause. It seems stuck valves are not unknown for these engines.
I am using Shell Rotella T4 15-40 oil. Now thinking some 2 stroke oil added to the gas might be a good idea.

Stuck valves are common if the tractor sits for some time. The C-60 has very weak valve springs.

I use Marine Stabil in the fuel and start the Cubs several times during prolonged no use periods, winter.

[Stoffregen Motorsports]

In engine terms, a valve can get stuck from too much heat, but that's usually exhaust valves. Improper ignition timing and/or bad fuel can also make them stick.

[ricky racer]

Can you better identify the issue? Does it feel like the valve stem is tight in the guide or is there something possibly hanging it up like a piece of carbon under the sealing surface? If you can move the valve up and then it comes down to the same position, there may be some foreign material holding it open.

[Schu]

Success.
Tap tap tap using wood dowel through the spark plug hole.
Many many hand cranks round and round using a screw driver to pull the valve down to free it up.
I have to say Cub valve springs are not very impressive.
I appreciate the help. Going to use Marvel Mystery Oil in the gas upon start up

[ricky racer]

[Stoffregen Motorsports]

Nice work.