I repowered a 19-inch lawnboy with a 4-hp tec engine. It was not that easy. I removed the engine off the lawnboy, Challange 1, the center hole was larger then the base of the TEC engine. Challange 2 under the lawnboy deck was not flat the fix was to cut and make the base flat, Next I cut the base of an MTD lawnmower and used that as a base to mount the TEC engine on the lawnboy. All was well till I tested the mower on real grass the shaft of the tec engine was at least 3/4" shorter, when I droped the wheels to compensate for this it was very difficult to push the mower due to the deck scraping on the grass/dirt. Buttom line I sold it for $350 ( lucky me) I would say I spent at least 8 hours dicking around with it . You may have better luck if you lawnboy as a smooth deck and the engine shafts are the same length.

When anything is modified be ready for a bunch of little changes you will have to make. Would I do it again NO!!!

I will see if I have the picture and if I do I will posted it.

Sounds like you repowered a 2 cycle with a 4 cycle. That would explain the challenges you had to deal with.

Mine is already a 4 cycle Tecumseh (5.5hp) so if I can find out which Tecumseh shortblocks interchange with the original engine (TVS120) it should be pretty straightforward.

If all else fails, I have a nice 10 hp Tec. engine which would make it interesting with some grabber green paint, but I need to find or fab. a blade adaptor for the 1" keyed crank.

Correction on the engine model no.: It is an LEV120 (361003A)

Looks like the newer "106" will work but not sure about the self propelled feature.

In case I end up using the TVM220 10hp Tec., does anyone know who sells a vast array of blade adapters (hubs) or even makes custom ones? I would need one that fits on a 1" shaft with a 1/4" keyway.