Re:
Alright, here's what we've tried/checked so far.
Main thing we do not have an answer to is the fact that it pulls plenty vacuum where the air filter mounts onto the mixer, but if you unhook the propane hose at the vaporizer that runs to the mixer, there seems to be zero vacuum pulling through that hose.
We've bypassed the filter and the solenoid in the propane supply line, both are working properly and it made no difference bypassing them.
We took the mixer and carb off of the intake, inspected everything, and put it back together with new gaskets....made no difference.
Checked every possible vacuum line, lines/hoses are in good shape with secure, sealed connections.
Took the vaporizer apart and there was a decent bit of oil in it, probably from the flop. The little sponge was totally saturated in oil, along with all the diaphragm parts. All diaphragm parts have been thoroughly cleaned and the sponge cleaned and restored....no difference.
Sprayed brake cleaner all around the intake where it mounts to the head while cranking, with no results in terms of firing. Does not appear that intake gasket would be the problem.
Take the air filter off and block off the hole with your hand and it will try to fire immediately....so that tells me there plenty of vacuum there, it's just not getting any at the propane hose that connects to the mixer.
If holding the button down on the vaporizer while cranking, it will crank and continue to run smooth and fine until throttle is decreased and it runs rather choppy at low rpm's, ultimately going dead if throttle is continuously decreased.
I still haven't had time during the day to call Buddy, but that's my next step. I'm completely frustrated with this, as I can't think of any other things that could possibly be wrong. We plan to do a compression test just for shits and giggles to make sure there isn't an issue with piston rings. It doesn't smoke at all and this issue happened so abruptly, I don't believe there's an issue there. I don't fawking know....pisses me off. Maybe there's something wrong with the mixer? The mixer is such a simple part, it's also hard for me to think there's something wrong there, too.