rearenginekarts.com

I ain't got no idea what it is, but it's worth $700. There is a guy on Ebay with an engine that at first glance looks like a Mac 91. However, he say's the only marking is GEM 1218 (The number on the chain guard) It pisses me off that cool stuff seems to fall into the laps of nimrods, and not me.

Mike,
that's a mc91 i think.
best i'd pay is about 400 but more like 300.
625 is insane as condition is unknown.
i'll be extremely surprised if he gets bids.
dave

The motor is a Mc91M/C.... look close and you'll see the plug where the compression release has been replaced. Thick top fin and ball bearing on PTO side.
Just needs to be painted red and white to look correct.... no telling what kind of internal condition you might find.
Steve O'Hara

I think many of us are frustrated when we see an engine on Ebay, with 47 pictures, none of which show the intake ports, exhaust ports, or even have the head removed. I love the statement "this thing sat in a shed for 39 years, and the carburetor may need rebuilt".

Good eyes Steve,
didn't even look that hard at it since the price he's asking was more than i'd pay
aaand always with the it's a rare vintage piece that i'm only asking 900$ for.
what a bargain.
dave

p.s. his start price has changed to 200$ with bin at 350$
D

I sent the seller a message telling him what he has and suggested he remove the exhaust and take pics of the cylinder, piston and ports. Haven't been back to see if there have been any pics added. Sounds like the price is more in line now.
Steve O'Hara