Thought I would pass this along in case it is of interest to anyone in the future.
I started having problems with my OC-46 last week. I went to start it last week, it ran for a few seconds and then died - sounded like fuel starvation. When I rebuilt it, I added an electric fuel pump and I know the 6 volt charging system doesn't charge so I figured the battery was too low (it uses a 12 volt battery to crank). After charging for a day, it started and ran fine yesterday for awhile and then died in the excavation - again, just like the fuel had been switched off. I managed to get it started again and got it back to the shop by running with the choke full on. At the shop I went thru the fuel system from tank to carb checking flow rate and everything was fine. In the end I found a tiny piece of silicon "gasket in a tube" stuck in the main needle valve (high speed mixture).
I have never been a fan of "gasket in a tube" and rarely use it so I know exactly where it came from! When I added the electric fuel pump, I gutted the mechanical pump and replaced the rubber diaphram with a metal plate - that was where I used silicon gasket material. (I left the mechanical pump and fuel lines in place so the crawler looked original but I don't have to crank the heck out of it if it has been sitting for months.)
I have never experienced silicon gasket material shedding thin whisps of material before but it is this time. I had the crawler quit once more in yesterday's work but, knowing the problem, all I had to do was pull the needle and blow it out - then it ran fine for the rest of the day.
If you use silicon, be aware that it can come back to bite you!
(BTW: I LOVE[/i] my little Oliver - what a SWEET tractor! I can see why they were so popular for "general work" and are still so much in demand by landscapers.)
never use silicone gasket sealer if it will come in contact with gas. it is not gas resistant.