Thanks for your help, the unit has been converted to propane only when i bought it, gas unit is no longer hooked up. here are somethings i did to it but im still having problems;
first i suspected there was a vacuum leak which not able to pull enough vacuum to open the regulator so i did smoke test, and smoke came out all around the old carburetor, and the throttle rod was slightly bent, and smoke came out from it.
Since its a BEAM brand and they were not longer making it, i bought a Impoco CA125M carburetor which throttle and bottom flange fits. i hooked up the vacuum line and propane line from regulator, when i try to start engine will crank but it wont start, right before i stop the key ignition the carburetor will have loud pop(backfire). I'm really lost and spent a lot time on it, any help will be appreciated and im willing to pay for help
Things i have done so far;
replaced new Propane Regulator
2. replaced head gasket and tested compression all 4 cylinders
145-150psi
3. installed new plugs.