Small Engines (Lawn Mowers, etc.): replacing old troy bilt engine, troy bilt tiller, tucumseh

Question
I want to replace the engine on my grandfathers troy bilt tiller(model# 20890) I think it's a 1969-1970? not for sure though?

The current engine is a tucmseh 6hp H-60 75500N.

My father restored most of it before he died except for the engine and it was working fine until the connecting rod broke after my nephew let it run low on oil, I was heart broken, many memories from this old machine..

I've found engines but they only have one shaft coming out of the engine this old tucumseh has two shaft's? both connect to pully's.

One shaft is the standard drive shaft the other is an extensions of the cam shaft?

I've heard of many people restoring these old tiller's and buying new engines that bolt up to the old base.

Am I missing something or do I have to find an old engine with dual shafts? or repair the broken rod and semi wore piston. I don't think I have the time to really do anything but bolt up a new engine if that it is possible.

Am I lost and confused or is ther hope of finding a new engine to bolt to my old war horse.

Thank's in advance for any help.  

Answer
Hi Elbert,

I'm not familiar with your tiller model, so I don't know the function of the second drive shaft.  If you do need it, then you will need an engine that has 2.  They may be available but I don't know where you could find one.  You might need to rebuild the original engine, in that case.  If you don't need 2 shafts, then you could just replace the engine with one that matches up.

Keep me posted,
Michael