Cantw8t,

Buying a used engine is like buying a used car. You can either end up saving lots of $$ and get a great deal, or end up having to deal with someone else's problems.

New and used Saito 100's are very easy to find. YS hasn't made the 91 for a few years so buying used is the only way to go. (By the way the YS 91 is a good bit stronger than the Saito 100). YS 110's sell out of stock even before they reach the US docks so it takes a little perseverence to buy a new one and there are very few used 110's on the market.

I bought a YS 91AC used earlier this year for something like $150 and it was a super deal. The engine looks and runs like brand-new. But you can never tell.

To be honest I'd recommend a Saito for your 4*, either the 90 or the 100, especially since you are new to this. Lots of folks know how to set up a Saito right but you are less likely to find good help at the field to help with a YS. And as much as I like YS engines, a YS would really be major over-kill for the plane.

Walt