Ford 8N issue

tlk

Member
I have a restored 8N - starts and runs fine for around 15-20 minutes and then just dies. Then will not restart. If I wait 30-60 minutes then it will restart and run a little while - any ideas?
 

OhioTC18

Well-known member
Gold Site Supporter
Maybe the vent on the fuel cap is plugged? Loosen the fuel cap and see what happens.
 

Doc

Admin
Staff member
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Yeah, good thought Jerry. Those are gravity fed and like if you put a finger over the top of a straw it will stop once counter pressure builds up if the vent is plugged. Good luck. Neat ole tractors.
 

bczoom

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If that doesn't fix it, my guess is you may have a bad coil.

The 8N's are notorious for that and a bad coil gives those exact symptoms. When the coil gets hot, it basically quits.

Do a google search for "ford 8n coil problems". Lots of info.
 

rlk

Member
Gold Site Supporter
If that doesn't fix it, my guess is you may have a bad coil.

The 8N's are notorious for that and a bad coil gives those exact symptoms. When the coil gets hot, it basically quits.

Do a google search for "ford 8n coil problems". Lots of info.

I'll second this as a bad coil. I had a similar problem on my MF 35 and it ended up being the coil. Fortunately they are not very expensive. Bob
 

tlk

Member
Ok need further help please - got a new gas cap but that was not it - keep drying.

Bought replacement coil - pulled old one off along with the gasket. Tried to put new one on but it will not fit down snug on top of the distributor. Even without the gasket I cannot get it to sit level - so took new one off and tried to put the old one back on and same thing - old one will not sit level. What the heck could be causing that?
 

rlk

Member
Gold Site Supporter
Ok need further help please - got a new gas cap but that was not it - keep drying.

Bought replacement coil - pulled old one off along with the gasket. Tried to put new one on but it will not fit down snug on top of the distributor. Even without the gasket I cannot get it to sit level - so took new one off and tried to put the old one back on and same thing - old one will not sit level. What the heck could be causing that?

I don't know what's causing it to not sit level, but does it matter? I have seen them sit vertical (on my MF), horizontal (in my boat), and leaning about 45 (in an old car I had one time) degrees. Bob
 

tlk

Member
yes - the coil drops down into a hole - plus the shape of the gasket and housing allow it to only fit one way. Very strange in that the old coil fit fine before I removed it. Now the old one nor the new one will fit back on properly. There does not appear to be any moving parts that could have shifted
 

tlk

Member
my 8N is 6 volt positive. I have a dumb question - it can also be set up as a 6 volt negative? What is the difference and is there an advantage of one over the other?
 

California

Super Moderator
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I think ordinary negative ground erodes the center electrode of the spark plugs faster than the side element so positive ground reverses this, and was a theoretical improvement.
 

bczoom

Senior Member
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my 8N is 6 volt positive. I have a dumb question - it can also be set up as a 6 volt negative? What is the difference and is there an advantage of one over the other?
That I haven't touched in probably 30 years and at that time, I was switching the 8N from 6V to 12V.

If you're going to change it, I'd look at what it takes to bring up to 12V negative ground and by doing so, bring it up a half-century of electrical. Pretty sure the instructions to do this are splattered all over the internet since so many have done it.
 

tlk

Member
Ok back to the drawing board! Replaced the gas cap and put a new coil on. Tractor ran 15-20 minutes again and quit. If I wait an hour or so then it will start up and run for awhile and quit.

any other ideas?
 

tlk

Member
I am thinking it may be the gas tank and rust etc clogging it up - I took the fuel bowl off and opened the valve and no gas ran out. I am going to take the entire bowl off and use a flashlight to see if there is a bunch of sediment in the tank - if I have to replace the tank is it a job I can do myself?
 
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