1949 8N Won't Start

[Bartman1959]

I tried to start my 8N today after a few months of no use, with no luck. It turns over fine, but just won't fire. I pulled a spark plug, cranked it over, and was getting no spark. I pulled the distributor, gapped the points to .025, and put everything back together. Still nothing. I have power to the coil with key on, and power to the alternator, but no spark.
The last time I used the tractor was months ago, and then I had rebuilt the carb, new points, plugs, and wires. Now, after sitting for a few months, no spark. Looking for some great advice here guys.

 

[pmsmechanic]

If the distributor is worn or if the points are gapped too wide then the points won't close. Take a test light and hook it to positive somewhere. Touch the probe to the negative side of the coil. Crank the engine. The test light should flash off and on. If it doesn't then take the distributor cap off and set the points closer so that the test light flashes when you open and close the points.

You can also open and close the points with a screwdriver when they are closed. If there is current then there will be a small spark at the points. If you do this then take the center wire out of the distributor cap and place it close to some metal on the tractor. You should be able to see and hear the spark as you open and close the points.

If you get a small spark at the points but none at the coil then there is something wrong with either the coil or the center wire. If you get spark at the center wire but none at the spark plugs then there is problems with either the rotor or the cap or the spark plug wires. Lastly remove a spark plug and make sure that it sparks.

 

[Bartman1959]

I'll try all that tomorrow. Thanks.

I forgot to mention, it is the front mount distributor.

 

[Phillip w]

.025 seems a lititle wide, but maybe for that applications it is right. I used to set a 390 Ford at .o19. Also, how about you condenser. I have seen them go bad and drive guys crazy (me included) trying to figure it out

 

[David_Kb7uns]

Worked on one 8n one time, the advance mechanism inside the distributor had worn through the insulation on the wire going to the points and was keeping the coil grounded when the mechanism rotated, the key switch was also a problem on that tractor.

David

 

[Bartman1959]

Didn't get a chance to work on the tractor today; hopefully tomorrow.

 

[Bartman1959]

.024 -.026 is what the manual calls for.

 

[Phillip w]

.024 -.026 is what the manual calls for.

Better stay with the manual. I had an old ford pick up i use to set at .019. That is were I got the number

 

[pmsmechanic]

Better stay with the manual. I had an old ford pick up i use to set at .019. That is were I got the number

Except if the lobes on the distributor are worn and a wider gap won't let the points close. Then you need to set the gap closer so that they will close. That's why I suggested to check at the coil with a test light.

A tight gap on a slow running motor won't matter. Point gap affects two things. Timing and how long the coil gets to saturate with electricity. All 4 cylinder engines have very similar point gaps. 6's and 8's each have their own common point gaps also. As the number of cylinders increases the gap gets smaller. The more cylinders on a motor the closer the gap as there are more lobes on the distributor. We are trying to get it running. Not give it a tune up. After it's running and we know why it didn't start then we can work on the finer points. (Pun intended)

 

[Bartman1959]

I'll try to get out there today and check the coil with a test light.