8n, 12volt Front distributor No power, quits after 20min

SoccerTopher

New User
I'm having a issue with my ford 8n stalling and lack of power once started. It will run for 20 min then start stalling. If I let it sit for 10 sec. it will start right back up but will stall sometime very quickly other times it will run for 5 min. If I wait 20 min it will run longer, sometimes.. Next problem when it is started, and I move the throttle lever quickly the tractor will stubble. The governor seems to be adjusting correctly when I do this..

I think I've done all of the 75 checks (not really but you get the point) and still haven't figure it out yet. Spark is good on all cylinders. 1/4 spark gap no problem. Compression 85ish, New points, coil, condenser. New plugs and wires. Made sure wires are copper core and they are hooked correctly. Checked all (3)fuel screens all clean. New carb, can remove the bottom bolt and fill a pint glass in 3-4 min. Have also check fuel flow as soon as the tractor dies, pulled the bottom plug on the carb and it keeps flowing. The governor seems like it's working correctly once the tractor is placed under load you can see it adjusting.

Just not sure what it could be.

This weekend I plan on putting electric ignition in it, just incase I'm having issues with point setup. I've swapped condensers, so I dont' think it's that.

I think its a fuel problem, because the longer it sits the longer it will run once start again. But I don't know since when I pull the bottom bolt on the carb gas keeps pouring out. One thing I did see is if I remove all the gas from the fuel bowl under the tank, put the bowl back on and turn the fuel on the bowl will not fill. If I crack the bottom bolt on the carb gas will start to fill the bowl. It's almost like the fuel inline is airlocked.

Any Help or ideas would be helpful.
 
(quoted from post at 13:09:04 08/16/19) I'm having a issue with my ford 8n stalling and lack of power once started. It will run for 20 min then start stalling. If I let it sit for 10 sec. it will start right back up but will stall sometime very quickly other times it will run for 5 min. If I wait 20 min it will run longer, sometimes.. Next problem when it is started, and I move the throttle lever quickly the tractor will stubble. The governor seems to be adjusting correctly when I do this..

I think I've done all of the 75 checks (not really but you get the point) and still haven't figure it out yet. Spark is good on all cylinders. 1/4 spark gap no problem. Compression 85ish, New points, coil, condenser. New plugs and wires. Made sure wires are copper core and they are hooked correctly. Checked all (3)fuel screens all clean. New carb, can remove the bottom bolt and fill a pint glass in 3-4 min. Have also check fuel flow as soon as the tractor dies, pulled the bottom plug on the carb and it keeps flowing. The governor seems like it's working correctly once the tractor is placed under load you can see it adjusting.

Just not sure what it could be.

This weekend I plan on putting electric ignition in it, just incase I'm having issues with point setup. I've swapped condensers, so I dont' think it's that.

I think its a fuel problem, because the longer it sits the longer it will run once start again. But I don't know since when I pull the bottom bolt on the carb gas keeps pouring out. One thing I did see is if I remove all the gas from the fuel bowl under the tank, put the bowl back on and turn the fuel on the bowl will not fill. If I crack the bottom bolt on the carb gas will start to fill the bowl. It's almost like the fuel inline is airlocked. what resistors are in the coil circuit?

Any Help or ideas would be helpful.
 
FUEL TEST: Place a container on the ground below your carb. Remove the fuel line from the Sediment Bulb at the brass fuel inlet elbow at the carb with a 7/16" flare nut wrench or equiv. Gently pull the line out and off to side so it points into the container. Open the Sediment Bulb 2 Full Turns. Observe that the fuel fills your container with a nice steady, almost pencil thick stream, uninterrupted and fills a pint jar in 2 minutes. Yes? Fuel test is fine at this point. Next, replace the line at the brass elbow inlet. You could remove the brass elbow and clean out the in-line screen filter while you're at it and before replacing the fuel line. Next, with container below the carb, remove the NPT plug one bottom of carb -it's the drain plug. Repeat Sediment Bulb with 2 turns and observe the fuel flow is as mentioned before. Yes? You pass and there's nothing wrong with the carb. You say fuel still flows when tractor off and drain plug pulled. Did you shut off the Sediment Bulb valve??? If not gas should keep flowing in system. I suspect you have some wiring issues, not fuel issues. Giving up and just putting EI on it is NOT a logical problem solving method. If you think it's a gas issue why would you jump into an EI system???

TPD
 
My response posted rather strangely, so here it is again.

what resistors are in the coil circuit?
 
From the toggle switch switch I think it goes to resistor assembly #A8nn12250A, then to the white resistor #8ne10306 to the coil. See diagram attached.
mvphoto41184.jpg
 
(quoted from post at 15:54:19 08/16/19) My response posted rather strangely, so here it is again.

what resistors are in the coil circuit?
eing sure the 12250 is in the circuit, remove the white resistor (put both wires on one terminal) and your problem will likely be solved
 
I have replaced the condenser twice and the coil is new also. Not sure how to test the condenser. The thing is spark look good when looking at 1/4 gap spark plug. I've pulled all the plugs and put my mangled spark "1/4 gap" spark plug in and the spark looks good and blue.

Thanks,
 

basically you are telling me to remove the white resistor, tie those two wire together that went to it and only use the #12250 resistor? Will try once I get home tonight.

Thank you....
 
SoccerTopher, I'm of the school, that 90% of the time ignition is the fault, BUT in your case you said it took 3-4 minutes to fill the pint jar. That's a long time. I would do what Tim Daley said and see why you can't fill that jar in 2 minutes.
 
(quoted from post at 16:55:53 08/16/19)
basically you are telling me to remove the white resistor, tie those two wire together that went to it and only use the #12250 resistor? Will try once I get home tonight.

Thank you....
orrect
 
Sorry, it's not a condenser issue. It's a wiring issue for sure but get the fuel issue set first. Baby steps, one issue at a time. Make sure your electrical is all squared away correctly BEFORE you power up the system -search "WIRING PICTOGARMS BY JMOR". He posted a taste above. With an 8N front mount distributor, switched over to 12 volts, you should have an alternator, with a NEG GRN set up and the generator and the VOLTAGE REGULATOR removed from the system altogether; the Ballast Resistor wired correctly; and a 1-OHM in-line ceramic resistor added ONLY if you have a 6V coil. If you have a 12V coil, there's no need for the additional resistor. When you do a front mount tune-up with new points and condenser, you should be performing a preliminary test procedure on the bench with your VOM -a continuity meter is all that is needed. Once the distributor passes the bench test it is ready to mount. Farmer Dan has a Front Mount test document put together. You can test the coil with your VOM set to OHMS. On the bench, STATIC: set your VOM to OHMS, place one meter probe (it doesn't matter which one, it isn't polarized or powered) on the coil pigtail connection and the other probe to the coil top wire terminal stud. You should be seeing 3.1 OHMS give or take and OHM with a 6V coil, double that with a 12V coil. That doesn't verify the coil will be good once powered under load. If you have ever left the key switch on without the tractor running, chances are you burned up the points for one, plus melted the insulating tar inside the coil and when it gets hot will short out and kill the engine. You need some very expensive test equipment to genuinely test a coil and most folks don't keep that stuff around.

Tim *PloughNman* Daley(MI)
 

Make sure you have full battery voltage from yer toggle switch switched side...

EZ way to eliminate fuel issues is to spray brake cleaner into the air filter inlet at the air filter are directly into the carb throat...
 
(quoted from post at 12:09:04 08/16/19) New carb, can remove the bottom bolt and fill a pint glass in 3-4 min.
You've drawn a fair number of comments on this piece of information. It does seem a bit slow and worth looking into, but I'm not so sure it's the cause.

(quoted from post at 12:09:04 08/16/19) This weekend I plan on putting electric ignition in it, just incase I'm having issues with point setup. I've swapped condensers, so I dont' think it's that.

DON'T DO THIS! At least not until you have figured out and fixed what is wrong. What happens if you have problems with the EI conversion? Then you will have two problems that you're trying to figure out at the same time.

(quoted from post at 12:09:04 08/16/19) One thing I did see is if I remove all the gas from the fuel bowl under the tank, put the bowl back on and turn the fuel on the bowl will not fill. If I crack the bottom bolt on the carb gas will start to fill the bowl. It's almost like the fuel inline is airlocked.
It's supposed to behave like this. If there's no exit at the carb end, the fuel won't fill the bowl. When you open the bolt on the carb, you provide the exit and the fuel can fill the bowl.

You mentioned that you checked fuel flow just after it stopped and that it was OK. Did you also check spark just after it stopped (you mentioned checking spark but not when).
 
(quoted from post at 18:15:04 08/17/19)
(quoted from post at 12:09:04 08/16/19) New carb, can remove the bottom bolt and fill a pint glass in 3-4 min.
You've drawn a fair number of comments on this piece of information. It does seem a bit slow and worth looking into, but I'm not so sure it's the cause.

(quoted from post at 12:09:04 08/16/19) This weekend I plan on putting electric ignition in it, just incase I'm having issues with point setup. I've swapped condensers, so I dont' think it's that.

My dad always that 90% of carburetor problems were in the ignition system!

DON'T DO THIS! At least not until you have figured out and fixed what is wrong. What happens if you have problems with the EI conversion? Then you will have two problems that you're trying to figure out at the same time.

(quoted from post at 12:09:04 08/16/19) One thing I did see is if I remove all the gas from the fuel bowl under the tank, put the bowl back on and turn the fuel on the bowl will not fill. If I crack the bottom bolt on the carb gas will start to fill the bowl. It's almost like the fuel inline is airlocked.
It's supposed to behave like this. If there's no exit at the carb end, the fuel won't fill the bowl. When you open the bolt on the carb, you provide the exit and the fuel can fill the bowl.

You mentioned that you checked fuel flow just after it stopped and that it was OK. Did you also check spark just after it stopped (you mentioned checking spark but not when).
 
Had a lot of rain this weekend, so my time messing around with it was shortened.

Does it run now yes, is running great no, just ok.

What I did so far:

I think the biggest problem was the double resistors. I removed the coil and measured the resistance at 3.1 ohms. Tested the ceramic resistor I had and it measured 1ohm so I disconnected the #A8nn12250A terminal block resistor. (I didn't like the connection to the wonky fiber core resistor). I'm now only using the 1-ohm white resistor #8ne10306. The tractor started and ran ok until a load is placed on it then it would stumble. The big difference is that it stayed running once hot. It ran for 45 mins steady with no problem. So I think once the dual resistors started to heat up, it was causing my stalling which was making me think it was a fuel issue.

Since I had already purchased the Electronic ignition I figured nothing to lose so I installed it. Once installed the tractor started and ran just like when I had points installed, but the lack of power, when given a load, has not been fixed. The tractor starts at the push of the button, idles at low and middle RPM. Once I get to the High RPM you can hear the motor start to skip a bit. It doesn't backfire or blows smoke, it just a skip every so often.
If I let the clutch out slowly the tractor will move and run fine when I approach a hill or any load the governer will start to move and that's when she will start to stumble and quit if it's to much load. If I jump on the clutch quick I can keep it from stalling and if it does stall it will fire right back up.

I've attached a video of it stumbling for everyone amusement. Just not sure where to go from here now.

Thanks for all the comments..

[video play=false:32000b4e15]https://forums.yesterdaystractors.com/videos/mvvideo41330.mp4[/video:32000b4e15]
 
A coil with a 3 Ohm primary needs no resistor at all.....now you have just one more to remove.
 

I'm happy to say I think I got it. I removed the ceramic resistor, (I have no resister inline from the coil to the toggle switch) which helped a touch, but I went back to messing with the carb to which I think had the biggest effect. I started to turn the main mixture screw out 1/4 turn each time loaded the tractor and repeated this until it didn't stumble.
Glad to say my family 8n for the past 42 years is back to its glory days...

Thanks for all the suggestions and help, This was a Happy ending.....
 

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