conversion of LP to gas question

We kept the existing tank for looks, and so we wouldn't have to change sheet metal. We removed the tank, removed all the plugs, washed it out with hot water and soap about 4 times. Put an air hose in it and dried it out for about a half hour. Then with the air running, we cut a hole in the top and welded in a 2" pipe nipple for a gas fill spout. I plugged all the propane fittings in the tank with pipe plugs. On the bottom of the tank we drilled it and brazed in a 1/8 pipe fitting to hose barb. We purchased a carburator and found that it would mount to the existing manifold if we used 1/4 bolts instead of 5/16. We had to drill the carb and the manifold out by about 20 thousanths and the bolts are kind of kinked in at an angle, but it holds tight and has run for 8 years. The other problem which we discovered was the lack of carb heat. So we added warm air induction to the manifold. We kept the original air cleaner and precleaner, but under the hood drilled a 2" hole horizontally into the air cleaner and put a duct over on top of the manifold. We then stuffed rags in the top of the precleaner so it draws air from around the manifold. You might not want to do this if you work your tractors in dusty conditions that need the precleaner but it has worked fine for us.

One drawback to how we did it is that with the 33 gallon propane tank, there is probably 4 gallons of gas in the bottom below the level of the carburator. Using the old manifold we are probably loosing some power, but for what we use these tractors for it isn't a big deal.

Hope this helps.