As wye8 said--the 2 really good TT engines are the 46 2stroke and the 91 FS.

The OS 61FX is not that big on performance either. It's a good sport engine--but it's no racehorse. And the darn thing costs $160.[:'(]

For the money, weight, and power--you might as well get a Tower Hobbies .75 engine. They cost $95 and they run like a raped ape. If your a Tower Super Saver Club member--then you got a 4yr warrenty[X(], and free parts shipping. Compare the weight of the .75 to all the 61 engines. It's crazy.

If you like ringed engines--you might do a search for the GMS .76 ringed and see how it stacks up.

I wouldn't touch an OS 91 2-stroke with a 20' pole. Just do a search here and you'll see why. For $200 the darn thing should run outta the box.

I wouldn't buy a 61 anymore. Just too heavy for the power you get.