8n issues

I just purchased an 8n model ford tractor and it will start and run great but after a few minutes it won't stay running unless I mess with the choke and when I try to mover it dies, I know cars but tractors not so much I think it's flooding or not getting enough air, any insight is greatly appreciated

Choking to keep it alive usually indicates you have a fuel delivery problem.

There are three screens in the 8N. 1 in the tank, 1 in the sediment bulb and finally there is 1 in the 90° elbow that attaches the fuel line to the carb body.

With fuel on, pull the pipe plug on the bottom of the carb. Allow gas to flow for at least a minute. You want to allow the float bowl to drain so you can evaluate actual fuel flow. Steady stream is what you're hoping for. If it begins to dribble, you will need to pull the individual strainers to determine where the blockage is coming from.

Oh! And welcome to the board!!

Pulling out the choke gives you a richer mixture. So, you could have either a fuel or spark problem.

A carb out of adjustment will also cause this problem; set the main jet at 1-1/2 turns out & leave it alone.

A dirty carb can cause the problem as well; as Dollar Bill said, start by cleaning the fuel screens. (see tips 45 & 56)

Dirty/old gas, or water in the gas can cause this problem.

Restricted fuel flow can cause this problem; remove the bolt at the bottom of the carb & check for flow. The flow should fill a pint jar in under 2 minutes.

On my 1950 frontmount, needing choke to run is the first sign that the points need adjusting/replacing.

A vacuum leak can do the same thing. Get a hand propane torch and carefully spray it (unlit of course) around the intake manifold at the carb to manifold interface & the manifold to block gasket of the tractor while it is running. Or, you can use carb cleaner or WD40. If it speeds up, you found the leak. Sometimes (rarely) manifolds crack or get rust holes.

Lastly, when all else fails, you could have an air leak around the carb metering section. The likely suspects are leaky throttle shaft seals and/or a worn throttle shaft. Or, just a real dirty carb w/ clogged passages.

Bottom line: Probably 90% of "needs choke to run" problems are fuel related, but do not rule out ignition problems, contrary to what others may tell you. I?ve had that very same problem before w/ a rebuilt carb, fresh fuel & good flow & a tight manifold.......and it was a spark problem. But, that was unusual. Just check the likely fuel problems first.
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