Need advice about my Johnson Iron Horse

[larry]

I was given a complete X-512. I seldom run across an engine where everything is still in place....all the linkage, throttle cable, etc.
It seemed like an easy cleanup and restore project. Then I noticed the wobbly carburetor. Uh-oh. Once I got a good look at it I saw what a significant problem I had. I'd hate to not be able to get it running again. I don't know if my only option is to try to find a replacement cylinder or whether a competent welder can recreate the missing piece. The part that's gone is gone for good so I have nothing to try to weld back in place. Please see the photo. Any thoughts?

[Gary Stewart]

I'm not a welder, but being cast iron, welding isn't easy. Another thought we kicked around.............

Take 1/8" steel plate and cut to size using carb manifold. Bolt plate to intake, drill, tap and countersink 2 small taper head bolts, 1 at 12:00 and 1 at 6:00. AM or PM won't make any difference! Remove plate, bolt to carb and drill hole for carb. Weld nut to back of plate. Put plate back on engine and JB Weld over the nut and dress up as needed. You might even want to 2-part epoxy the plate to manifold.

[larry]

Thanks Gary. That idea sounds very workable. It will likely be the path I follow. I'll update my progress in the weeks (months?) ahead.

On another note.... this is the first time I've ever worked on one of these engines. I find the design very interesting. It's simple, that's for sure, and easy to work on. The cylinder jug / valve housing is a very rough casting. It seems no effort at all was expended to finish it for appearance sake. Once the cylinder is removed, the crankcase looks hunchback. Also, instead of the bottom of the cylinder jug being open right into the crankcase it's pretty much closed. There's just a rectangular slot for the connecting rod to pass through. I love how easy it is to remove and install the valve keepers. Instead of two clamshells it's just a pin that passed through the valve itself. Push down on the spring, pull with a pair of needlenose pliers and you're done. Of course you have to remove the cylinder to get at them! Then there's the large bolt in the head...right next to the spark plug. It goes straight into the combustion chamber. I have to wonder why it's there.

[bushguy]

a piece can be made from steel and bronze welded very easily the cast and steel both take to bronze .

[scottcerveny989]

if you do weld it... you have to preheat the cast before the weld. and then heat up again after weld. and submerge in sand so it cools down slow. or else it will crack.