Got my 8n running again still issues

[ErikL97]

Finally after 2-4 months the old tractor finally gets a road test.

I’ve had to buy a new carb, and a new coil and A new distributor ,also a new resistor.

My old carb cracked and broke at the fuel inlet, tired to repair it didn’t work. The 8n didn’t have a resistor it is 12v, I burned up 2 coils before we found out my resistor wasn’t there. Got all of this fixed. Also have new spark plugs there about 2 months old.

Now today while driving after the new carb is on, I notice it was back firing, and running rough. Did have to ride back with the choke out. Gas cap is vented I’ve drilled a hole in it. I was getting good gas flow but I didn’t check the carb plug yet. I do have the breather off.

 

[Eman85]

If it needed the choke closed to run you have a lean condition. Somewhere you are not getting enough fuel in the cylinders. Have you adjusted the carburetor at all? Checked for a vacum leak?

 

[ErikL97]

If it needed the choke closed to run you have a lean condition. Somewhere you are not getting enough fuel in the cylinders. Have you adjusted the carburetor at all? Checked for a vacum leak?

no I haven’t I bolted it up only thing I did was turn the main to close and did the 2 turns. Haven’t checked for a leak last carb I didn’t have any issues maybe now I do.

 

[BodaciousGaming]

You need to tune your carb. See attached (assuming you have a Marvel Schebler and not a Zenith; unlikely but calling out the possibility)

 

[soaked]

Agree, tune carb.

Unfortunately that pdf manual only mentions the back suction circuit in general, and doesn't give the full description ( that is in the other manual.) Guessing its for newer tractors without the jet?

If back suction is too much, pulling the choke can help. If a new clone carb, it may not have come with the proper size ecomomizer jet, or may be missing the jet entirely.
.076" is too big, and causes a lean condition, surging, hesitating, from ~1/3 throttle and up.
.046-.052 size run good, from my experience.

Here is that info.

 

[DanielW]

Good luck tuning the carb - a lot (I'd say the majority) of aftermarket N carbs have the needles and seats machined different than the original, so tuning them is a pain, and it's even more of a pain to get them dialed in well. Start with the stock settings from the manual, but don't assume they'll be correct for the aftermarket carb.

Another common problem for N's sucking air is the manifold coming loose. Do a quick check of all the manifold studs/nuts to make sure they're all tight. Even if they are, it doesn't necessarily mean it isn't leaking around that gasket surface. But it's a quick/easy thing to check.

 

[ErikL97]

Got back out to the tractor over the weekend.. Was getting great fuel, had to charge battery, got it to run, went to tune and it went dead. Took the line off checked fuel flow wasn’t great, so checked the fuel assembly, it was clogged once again, gonna drain the gas back out and take the tank off again, last time I cleaned I thought I had everything removed but I guess I didn’t maybe missed something. The debris looks like rust flakes I assume. I do have a filter in the gas can I use and I make sure it’s clean before I pour the gas. Even make sure the can is clean before I fill just in case.

 

[soaked]

I see the price on a new tank is back down here

 

[ErikL97]

I see the price on a new tank is back down here
View attachment 152746

New gas tank on the way.

 

[soaked]

Remember to check that the vent hole is clear
IIRC each of the 3 tank bolts went through a thin strip of leather that separated the tank from the supports. Rubber cut from an inner tube works nice when the leathers are no good.
John

 

[ErikL97]

Remember to check that the vent hole is clear
IIRC each of the 3 tank bolts went through a thin strip of leather that separated the tank from the supports. Rubber cut from an inner tube works nice when the leathers are no good.
John

The new tank install went well and I’m getting great gas flow. Only thing is now when running my tractor runs great in low rpm. When I get it to high rpm’s it will run rough and back fire. Maybe I still need to tune the carb for this or is this another issue.

 

[soaked]

That's great the new tank is installed.
What carb is in use?
Could try unscrewing the main adjusting needle to see if it improves, like this:

D

Thread 'Ford 8n surging'

Apr 7, 2020

My ford 8n started surging and I replaced the fuel tank with a new one, new tsx241b carb, new fuel shutoff valve, new fuel lines. The tractor still surges.
If I remove the mail needle valve completely from the carb the tractor runs just as smooth as can be and has lots of power and no surging. I then put on
another tax 241b new carb and the same thing happens. Surges at half to full throttle idle fine put under load starts surging badly remove the main jet
runs smooth again
Forgot the 8n is a side distributor engine.

• Dal47
• Replies: 9
• Forum: Ford 9N, 2N & 8N

If it still runs bad, check to see if spark will jump 1/4".

 

[ErikL97]

That's great the new tank is installed.
What carb is in use?
Could try unscrewing the main adjusting needle to see if it improves, like this:

D

Thread 'Ford 8n surging'

Apr 7, 2020

My ford 8n started surging and I replaced the fuel tank with a new one, new tsx241b carb, new fuel shutoff valve, new fuel lines. The tractor still surges.
If I remove the mail needle valve completely from the carb the tractor runs just as smooth as can be and has lots of power and no surging. I then put on
another tax 241b new carb and the same thing happens. Surges at half to full throttle idle fine put under load starts surging badly remove the main jet
runs smooth again
Forgot the 8n is a side distributor engine.

• Dal47
• Replies: 9
• Forum: Ford 9N, 2N & 8N

If it still runs bad, check to see if spark will jump 1/4".

The marvel it’s a clone my old one broke around the fuel inlet. I had a tractor supply brand carb and it wouldn’t work I tried everything just to send it back. Will check my plugs. Also I have a weak battery I have to charge it. I’m just curious if my alternator is charging my battery. Spark plugs are new. Just really black I guess from rough