Trust me, they do. They have been known to tip over or get landed into all sorts of things!

Quoted from mullacharjak

What if you buy a pusher or a trike engine. They dont  have prop strikes .
KK

Have to say that with my own eyes I've seen several wrecked props on weightshift trikes after bad landings. That's how I know how an Ivo is constructed!

I watched a powered parachute guy get his lines into an Ivo Prop on the ground....instant disaster.

I almost never comment on anything to do with engines as I don't consider myself a mechanic, though oddly people used to bring me outboards that mechanics had given up trying to get to run and I seemed to be able to sort them out.  However someone above touched on the inherent risk in buying used engines.  One way to save some money and avoid this, if you have the confidence to follow manuals, is to buy an engine kit and assemble it yourself.  You save money, get a new engine, and you won't be hesitant to tear it down and check things out if you do get a prop strike.  Just a thought.  It's the way I'm most comfortable to go.

Tom

Quoted from Tom

Ibuy an engine kit and assemble it yourself.  

The only engine kit I'm familiar with are for full size VW engines.  Of course it's possible to make a 1/2 VW from one of them....is this what you mean?  I once built a 1/2 VW engine and it turned out to be the most unreliable engine I've owned.  It lasted 32 hours before self destructing.

I would always recommend buying a new engine first; or a used engine from a well known overhaul shop.  

Though there are other kits out there, I was indeed thinking mainly of what I guess we'd call "VW technology" engines.  However I would want to make clear that I wouldn't use a "conversion"  of an actual VW automobile engine.  The really good engines in this category don't really have any Volkswagen made parts in them any more.  Everything from the cases on up are made for high performance use from parts made specially for this purpose.  There probably should be another name for this type of engine.  My favorite, though one of the most expensive kits is the Aeroconversions one, though that would only be OK for something like the "Epic Sport" I'm building so slowly.  There are other kits for "1/2" type engines, suitable for anything down to ultralights.  Built from high performance parts, not a very scientific term, there is no reason not to expect a reliable engine.  These are a lot less expensive than other fully comparable fully assembled engines.

Tom

A Rotax 503 Prov 8 is a reliable engine if run properly.  While there are a few new ones(new old stock) floating around, most are used because Rotax quit making them in 2012.

I would not be worried about a used 503 Prov 8,    rebuilt by a reputable Rotax repairman.  

Or you can overhaul one yourself,  they aren't that complicated. The most expensive thing will be if you have to replace the crankshaft.