[bleoh]

Hi all,

I have an 1872 with a very tired engine and I have decided to replace the M18 with a CH18S. I did some research here and picked up an 1863 for the engine and other parts. The 1863 has about 700 hours on the meter and seems to run great. Just looking for you folks to look over my shoulder to check my plan.

Use the 1863 engine mounting plate to locate the front PTO.
The 1863 engine will have the correct muffler and heat shield to use in the 1872.
Will need to add an air duct on the flywheel side to stop recirculating hot air for cooling.
Front PTO pulley on the CH18 is larger (6" I think) and I will need to use the PTO from the 1872 or get a new PTO with 4.5" pulley.
May need to modify the air cleaner cover to clear the firewall.

Parts I am not as sure on:
Driveshaft, use the 1863 shaft as it currently connects to the CH18 and upgrade the pump side to eliminate the rag joint style. To do this I would need an adapter and a user here, JeffinPA, sells those. Then I would need to lengthen the driveshaft. I am thinking a short piece of tube with the correct ID and cut/sleeve/weld the 1863 shaft to the needed length.

Wiring: current setup shuts off by grounding the coil, I still need to do some research to make sure that will work on the new ignition system.
Find a circuit that will energize the fuel valve on the carb. I have not figured this out yet but hoping there is a leg of the charging circuit that is hot in the run position only. What have others used?
I think there is an oil sentry system on the CH18, was wondering if that was worth retaining?
Need to look into how to hook up the oil pressure light currently in the 1872. Is there a pressure switch on the CH18 that will work?

Any other conversion issues to consider that I have missed? Any other parts from the 1863 that will swap over to the 1872 that I should consider such as the mule drive?

While the engine is out I am going to make sure all the fins are clean. I gave it a full tuneup and oil change and have been using the 1863 for a few hours now and don't see any leaks or other issues. Is there anything else I should do to it while it is out? Head gaskets, de-carbon, etc...?

Thanks, and sorry if some of this stuff has been covered. I feel like I have started to go round in circles with my searches here.