Hi,
I am trying to troubleshoot my mom's old Hardwick Stove (model
ZKC9732C-320A), which runs on propane.

The stove burners are all Ok. The problem is with the oven

There is the line in, which connects at a hand valve to the pipe running
around under the burners, and has the 4 stovetop valves/pipes and 1 oven
valve/pipe running off of it. The stove dial is on a valve that is no
longer stocked. It has a line running in from an oven
thermostat/thermocouple, two small gas lines out for pilots to the stove and
broiler burners, and two gas lines out to valves for the stove and broiler.
(These valves are operated by pilot thermocouples).

I turn the stove on to 300, and after a couple of minutes it kicks on, and
then off, and on-off intermittently, only enough to get it up to around 175
or maybe 200 degrees. It will literally turn on for about 5 seconds, and
then turn off again. It's like a valve is flakey, but I don't know whether
it is at the dial valve or at the valve with the pilot thermocouple
underneath. Since it could be either valve, or even a thermocouple, not
sure where to test further.

I have taken the stove thermostat out of the stove, and it still behaves in
exactly the same way, so reaction of the thermostat to heat in the stove
isn't presenting this issue. I'm still wondering how to figure out if it is
the valve at the dial, or the valve underneath (with the pilot thermocouple)
that is causing this (or both).

Is it possible that I could find a generic part for replacing the stove
dial/valve assembly? And is it possible that I might try to clean the old
parts out, maybe there is a bit of crud in there? I thnk of course that the
main dial valve is at least 25 years old by now. The stove valve underneath
(with thermocouple) has the number Z-77218-12, and 90428 on it.

Thanks for any help in advance -
Mark