Propane check this out

Ahh that makes more sense. I was wondering what kind of modification would have to be made to the carb not to mention a way of injecting the oil in the right manner and timing. Thanks for clearing that up.
 
Ahh that makes more sense. I was wondering what kind of modification would have to be made to the carb not to mention a way of injecting the oil in the right manner and timing. Thanks for clearing that up.

Not much at all... a carb doesn't really care if the fuel is gas or liquid. You just have to figure out a way to regulate the propane.

The oil doesn't get injected into the combustion process. It is squirted on the underside and skirts of the piston for lubrication.
 
Propane is a hydrocarbon gas. Oil is a hydrocarbon liquid. Propane can and will dissolve into motor oil, just as will most gases to a greater or lesser degree. As a quite small hydrocarbon molecule surrounded by an environment which is predominantly much larger hydrocarbon molecules, the propane can and will react with the oil to some degree, which may result in a variety of reaction products - some of which will not be effective lubricants. It is pretty much the same in gasoline fueled engines, which is why tars and such accumulate over time.

With propane fuel, due to the size of the propane molecule, the reaction rates will be somewhat higher on average than with gasoline. Like I said, not likely to actually be a problem, but the potential does exist. Just change the oil occasionally, as with any engine.
 
vtec, a carburettor cares very much if the fuel is a gas or a liquid. To operate correctly a gaseous fuel carb must be used. I had a friend run a small one cylinder generator on propane with a stock gasoline carb to charge a battery. It worked marginally at very low propane pressure and with the choke closed, but he couldn't vary the speed of the engine or put a heavy load on the generator without stalling it. These engines shown here have a propane pressure regulator and a gaseous fuel carb to operate properly.
 
Propane is a hydrocarbon gas. Oil is a hydrocarbon liquid. Propane can and will dissolve into motor oil, just as will most gases to a greater or lesser degree. As a quite small hydrocarbon molecule surrounded by an environment which is predominantly much larger hydrocarbon molecules, the propane can and will react with the oil to some degree, which may result in a variety of reaction products - some of which will not be effective lubricants. It is pretty much the same in gasoline fueled engines, which is why tars and such accumulate over time.

With propane fuel, due to the size of the propane molecule, the reaction rates will be somewhat higher on average than with gasoline. Like I said, not likely to actually be a problem, but the potential does exist. Just change the oil occasionally, as with any engine.

That's interesting. I used to maintain a fairly large fleet of forklifts years ago. Most of them ran on propane (indoor use). The Continental Red Seal engine rep always recommended extendiing the oil change intervals 2-300 %. Of course he was concerned by combustion by product contamination rather than direct contamination. I also checked out a standby genset for a radio station transmitter site in Northern Michigan. It hadn't been run in 40 years according to the paperwork involved. As a matter of fact the propane in the 500 gallon tank was 40 yrs old according to the delivery ticket still in the folder under the cover. It was a 2 cylinder *water cooled* Wisconsin engine. I did change the oil which looked like brand new oil from 40 years ago. The only other thing I did was clean the points and it fired right up....quite a shock to me. Considering that I was being paid to get it running, and not hourly, I was quite pleased.
 
The way that propane (gaseous fuel) carburetors work, if the engine isn't running there is essentially no propane in the engine, so nothing to react with the oil. As long as the engine is well sealed so you don't get serious water condensation insie the engine, it will stay good.
 
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