Ford 8n - Must Have Choke Out

[blount2000]

Thanks for posting the results blount and glad to hear you got it fixed. Part of the fun with these old tractors is keeping them running. Maybe it's just me but I enjoy wrenching on old iron.

I did enjoy the task of making this repair successfully. It was unfamiliar to me, and I learned quite a bit from the process and gained confidence that I could do it again down the road if needed.

My son was helping me, and when the repair worked he could tell I was proud of it. He said: "So I guess you think you are a tractor mechanic now?" I laughed and said "Not hardly!"

 

[blount2000]

It has been a season or two since my carb rebuild, and the tractor had started running a bit rough again. I took the carb off and soaked/cleaned everything like before, and it seemed to do the trick once again.

However, now there is a new problem. When I put the carb back on and got the tractor cranked, there is gas leaking out between the two halves of the carb (see pic below). I used a brand new kit so the gasket is fresh.

This is probably a dumb question, but is a bad / non-sealing gasket the only thing that would cause this, or is there anything else it could be? I'm planning to take it apart and then put it back together to see if that fixes it, but it would be good to know if there is any chance that there is some other underlying problem (that I may have caused) that would cause it to leak.

Thanks in advance for any insight!

 

[EarPlug]

Did you replace the gasket? Gaskets are frequently damaged with removal. Also, they take a "set" from the original install and won't be the same shape when you put it back together.

 

[3Lfarms]

I think the fuel level is too high. The gasket should not be below the level of the fuel.
That would seem to indicate that either the float is misadjusted or the needle and seat are leaking.
If you did not change the float setting, I suspect your new needle and seat in your kit need to be lapped together to get a good seal.

 

[blount2000]

Thanks for the responses. It was indeed a new replacement gasket, which surprised me when I saw the leaking.

I didn't intend to adjust the float, but that doesn't mean I didn't inadvertently bend it or something. That makes sense what you are saying about the gas level. I guess I never thought about the gas level not supposed to be up as high as the gasket. Guess it can't leak out from between the halves if it doesn't reach where the halves meet!

I'll try to adjust the float tomorrow when I take it apart and see if that does the trick.

 

[RalphVa]

I was going to suggest adding some Seafoam to the tank. Have had lawn mower engines where I had to keep the choke on. Added Seafoam. Fixed it.

Ralph

 

[RickB]

1. Float level is too high.
2. Faulty needle valve.
3. Loose needle valve seat/bad seal between seat and carb.
4. A speck of dirt allowing leakage between the needle and seat.

 

[ericm979]

If it doesn't have a fuel filter, put one on.

 

[pmsmechanic]

So as mentioned there is probably some thing not letting the needle valve seat to close off the flow of fuel into the carburetor. What I like to do before I take anything apart is shut the fuel off at the tank and run the engine till it dies. Then turn the fuel back on and see if the rush of gas into the carburetor has washed whatever out of the needle and seat. If the leak stops your good to go. If not then you'll probably need to take the carburetor apart. Might be a good idea to install a fuel filter in the gas line.

 

[blount2000]

I tried shutting off the fuel & letting it run out and then turning it back on, but unfortunately the leak was still there. So I took the carb off, took it apart & cleaned, adjusted the float, and then put it back together.

The leak appears to be fixed, so that did the trick. The float level gap actually had to be adjusted downward. The gap was larger than the 1/4" (which to me seems like the float would be making less fuel stay in the bowl), but I adjusted it to the 1/4" and all seems to be well.

Thanks to all of you for your help.


There were a couple mentions of putting on a fuel filter, but mine has metal fuel lines. Do you have to cut out a section of the metal lines, or is there something that gets added at the beginning (or end) of the existing metal lines?