I know that nobody knows for sure, but what would your wild guess be as to how many gallons of fuel could be run through an OS four stroke before it would be worn out? I am buying an engine that has a couple of gallons through it and was wondering if this is very much?

Thanks

A couple of gallons is nothing. Just broken in.

Joe

Hello; I don't know about OS, but I have an old Saito 45 that has had more then 66 gallons of fuel though it. I started counting in 1991, after I put new bearings and a new piston in it. My own longest living OS engine is an old 90, the type with the pushrods going up the back. That one has run (for me) since 93. I think that as long as you can get parts for it, theres no reason why it shouldn't last forever.

Longevity also depends on how you care for your engine. If you tend to run your engine lean and/or use fuel with insufficient amount of oil, then of course your engine will not last that long.