I have not updated in a while. So here is what has been going on:

Generator has been repaired, the number 1 cylinder had a bent valve end where it meets the lifter. It looks like at some point in the past the valve got stuck and the valve end was bent. Someone broke it loose with vise grips and continued to run it this way. The bent end caused the valve to push to the side and wobble out the valve guide. I replaced the guide and the valve and installed a new gasket set while I was in there.

I managed to find an original manual for the gen set that was full of useful info like the part number for the stock muffler which I found online for $12. Other info like the make and model of the power outlet and stuff like setting the velocity governor were handy to have too.

I could not find one of the original cast exhaust couplings so I just made my own. I got a flange from he local muffle shop and made the rest out of a 1-1/2" rigid conduit sweep and various pipe fittings which replicated the original pretty closely. It runs much quieter now, in fact the noisiest thing about it is the cooling fan.

One thing I discovered during all of this is the propane conversion that was done would not work at any useful power output. The setup on the generator as I got it was to use vapor from the propane tank. From figures online I would need a 250 gallon or bigger tank to be able to keep up with the vapor demand without freezing up. I picked up a IMPCO vaporizer off ebay and installed it in the place of the gasoline engine heater. I bought a ASME 30gal propane tank off craigslist to feed it, that should give me about 24hrs run time at minimal load and about 12hrs at full load. The generator and tank were mounted to the trailer I picked it up with.

The power plug that mates with the connector on the generator is still made, but costs over $600. Even one on ebay is over $200. I ended up making a pigtail with a twist lock connector on it that connects to the output studs on the panel. This connects to the 50' of 6/4 SO cord I am using for an extension.

I still need to make the replacement back and top covers, that can wait for now.

Tank mounted to trailer:

New vaporizer: