8N Help

[PitbullMidwest]

I'm hoping that somewhere in this vast storehouse of knowledge some one can help me.

My in law's 1948 8N has developed a problem. It will run smoothly for about 5 minutes before developing a miss and then acts as if it is starving for fuel. If choked it will continue to run for a little longer. It starts up immeadiately after dying (requires choke to re-start which is unusual) and repeats the same process.

So far I have drained the tank, checked the glass fuel bowl for sediment, drained the fuel line and stuck in fresh plugs. It really acts like a fuel problem but I need some suggestions.

 

[Bird]

</font><font color="blue" class="small">( acts like a fuel problem )</font>

I agree. Sounds like it's about time to tear down and clean up the carburetor which might require a "kit" with gaskets and such.

 

[MJB]

Check that the vent in the fuel tank is not plugged. It may be pulling a vacuum on the tank. If it runs OK with the gas cap off you've found your problem. Good luck.

 

[Bird]

Thanks, Michael, I just plain forgot about that. /forums/images/graemlins/frown.gif It would be a shame to tear the carburetor down first and then find it was just the gas tank vent. /forums/images/graemlins/laugh.gif

 

[PitbullMidwest]

Ok, I'll try that tonight. If it is the vent, where's it located?

 

[Youare]

If there is a Tractor Supply Company near you they have carb. rebuild kits on the shelf which are the same as the Ford/NH dealer sells around here for less than $20.00.

I put a kit in my 8N not too long ago just cause I thought it wouldn't hurt. They are really easy to rebuild, adjust everything by the instructions and you should be fine.

The vent should be part of the cap on the fuel tank.

I replaced the sediment bowl and fuel shut-off on mine also. I had some rust build up one time right at the shut-off on the sediment bowl which did the same thing you experienced.

You can check this out by removing the bowl and opening the fuel shut-off. My shut-off has a reserve setting that is related to the number of turns it is opened, you may want to check this out also.

Randy

 

[bgott]

The vent in an 8N tank is built into the top of the tank. If you take the hood off you'll see a bubble built into the top of the tank. They built it this way to keep fuel from slopping out when the tank was overfilled. You can run the tractor with the cap loose to see if the problem goes away. Another thing that will screw you ( it screwed me, anyway!) is the screen on the brass elbow going into the carburator fuel bowl. Unscrew the fuel line from the carburator and then remove the fitting it screws to. There is a screen on it if someone hasn't chunked it.

 

[gator]

Had this exact problem in my 62 Allis D-12. Was caused by rust in tank breaking loose and plugging up petcock. Could tell by air pocket on top of gas in sediment bowl. The only real fix is to take tank off, clean inside (lots of different ways to do this) and coat inside with liquid tank liner, otherwise it just keeps on happening. Thats a common problem with older gas tractors with steel tanks. The discussion page (top left corner has link) at www.allischalmers.com has lots of advice on how to clean and what to use to coat tank, though you'll probably have to search for it.
P.S. I originally thought it was my tank vent to, tried loosening the cap but did not change anything.