Bought a G705 LP that was on gas, and got all the parts with it to go back to LP. Runs great on a forklift tank after cleaning the regulator and mixer. I put about 2 gallons of LP in the main tank by backfilling it with a hose from the forklift tank, but the engine barely idles off the big tank. Probably just not enough LP in there yet. The tank had a little pressure on it when I got it, but had been sitting a long time. All valves and lines are fine. Could there be too much air in it? Will filling it solve the problem, or should it be hooked to a vacuum pump to get rid of the air? Hate to put a bunch of LP in it, then have to take it out.