Hi Steve, A friend, same guy who destroyed the roto tiller engine, ran a chain saw on straight gas for over a year. And when I told him he needed to mix oil with that gas, he didn't believe me and I don't think he ever changed his ways. He moved away so I lost track of the end of that story. I suppose there is a certain amount of lubrication in regular gasoline. Hey, when it gets slow on the list, why don't you tell us about that boat you're building. Rick Langer M15 #337
Date: Tue, 22 Mar 2005 23:37:14 EST From: IDCLLC@aol.com Subject: Re: M_Boats: Re: outboard fuel shutoff To: montgomery_boats@mailman.xmission.com Message-ID: <84.41dd88fe.2f724c7a@aol.com> Content-Type: text/plain; charset="US-ASCII"
When I rebuilt my Tohatsu 2.5 (seized up due to dead water pump; ignorant me) the bottom end was oily. The bearings consist of ball and needle bearings. I'd say that you'd have to run one a long time to hurt the bottom end (a friend of mine ran a 2-stroke inboard most of one season on straight gas before realizing it was a 2-stroke after it finally seized up. It smokes a lot now, but still runs).
The lean burn issue is less clear. On a 2-stroke, there's not much to burn, and the parts in question have a lot of relative mass, thus could absorb a lot of heat in the short term. On a 4-stroke, the exhaust valve would be in danger, but the motor should be a lot cooler than a full throttle situation, and again, we're talking about a no load, short term situation.
I frequently run 2-stroke equipment dry. No ill effects so far. Come to think of it, the lowly lawn mower can expect to be run dry while in working mode, again and again. Hey, wait a minute, so can outboards! How many of us have forgotten to open the gas vent? (Me.)
All that said, if your motor melts into an expensive blob, not my fault! I hereby limit my liability to $0.02 ;^)
Steve Tyree grease monkey and shade tree mechanic