Compression checks out good- no head gasket issues. Change the engine oil ( I reccomend SAE 30) & run engine at least an hour- let the engine get good & hot. Do this on a weekly basis & it'll bake the moisture out of the engine.

The propane system sounds like it's time for a rebuild. Make sure you're running HD-5 propane ( if you want to keep your propane system clean for as long as possible). I reccomend replacing the propane shut off solnoid, regulator & carb diaphram- total cost is under $500 (if you replace these items yourself). That should keep you up & running.