[SSG]

It's a late 40's oliver 70, 6 cylinder gas with a zenith carburetor.
When starting this tractor cold, it will start with choke and run for ten seconds or so and then shut off. After that it refuses to start again unless it sits for a while and then you can try again, sometimes it'll do the same thing again, sometimes you can get it to stay running. If you can manage to get it running, it will run all day long. It'll restart easily after its warmed up. The whole tractor was totally rebuild a few years ago, so everything is in good shape. It's still on 6v so it doesn't crank very fast or for very long, but it ran fine before this issue popped up.

I pulled the plugs when it's refusing to start and they are dry and don't smell like gas even after attempting to start it with full choke, so it's not flooding.

I really think it's carburetor related, I had assumed the float bowl wasn't refilling, but I pulled the carb apart and it wasn't really dirty. I sprayed it out and blew out all the passages with air, installed a new float needle, seat and spring and put it together with new gaskets, no difference. The sediment bowl is clean and it seems to have good fuel flow to the carburetor. The gas is fresh.

This tractor really has me puzzled. Anyone have any ideas?

 

[dave_r]

try a bit of starter spray in the intake when this happens. That would tell you if it's a fuel problem or something else.

 

[SSG]

I didn't have any starter fluid handy, plus it's kind of tough to get in there due to the air cleaner pipe design. I blew out all the fuel lines, filter base and fuel valve with compressed air and that seems to have made a difference. It's still very cold natured, but it will restart now with a lot of playing around with the choke.