'I don't know if this will help you. It is my experience with a 180 hp
Franklin having the same problem, sort of. I only had 3 exhaust valves in
various stages of sticking.
I pulled the valve cover off, and the rocker arm assembly off. Then
removed the bottom sparkplug, to gain access to the exhaust valve stem from
inside the cylinder. Since the valve was stuck the next part was fairly
easy. I remove the valve spring keeper and springs from the valve. I then
started tapping the valve with the butt of a screw driver, to move it back
into the cylinder. Once I got the tip of the valve flush with the valve
guide, I reached through the sparkplug hole and grabbed the valve stem with
a set of mechanical fingers (two finger variety) so I would have some
control of the valve should I drive the stem completely out of the valve
guide.
What I found was the inside of the valve guide was coated with a thin
crust of burnt oil. It had a dark amber/brown look to it. I then took a
pair of tweezers that had a well rounded tip on it, and rubbed it over the
crust with a moderate pressure and was able to break up the crust. I used
just enough pressure to break the crust and used a rounded tool so I
wouldn't scratch the valve guide or remove any metal.
For further information, I tried Marvel Mystery Oil, and about every
idea that any one would come up with. The colder the motor was, the worse
they stuck. Over time, it only got worse. I did make a fixture that I
bolted to the head that enabled me to collapse the valve springs so I could
get the keepers off.
After I got to the point that I knew what I was doing, it took
approximately 1 hour from start to finish to free up one exhaust valve.
Bob Etter
PO Box 974
Tonopah, NV 89049
775-482-6820
rletter@citlink.net'