New thread, same problems... 8n won't start

Twitcher

New User
Hi guys.. I have learned a ton from you ppl. I've been lurking in the background reading and implementing but I've finally hit the proverbial brick wall.

I have a 1948 8N that I recently converted to 12V... tractor has all new wiring (including battery (50V 2GA) connections and spark plug wires (stranded copper)). I used this diagram: http://www.myfordtractors.com/12volt03.shtml (EARLY 8N FORD TRACTOR FRONT DISTRIBUTOR?12 VOLT?1 WIRE) which I followed to the T. I have checked all connections to make sure there is continuity and power. Double checked the ground to make sure there is good contact.

I have a new coil that is 12v, 3 ohms giving me total resistance of 4 ohms when the new ballast resistor is added in. I have new points (gapped to 0.025), new condensor, distributor cap, rotor button, spark plugs (AL 437 gapped to 0.025), ammeter, and ignition switch. While checking to make sure I was getting spark at each plug, the bendix on the started decided to explode... so I now have the new rachet style bendix on the starter.

Battery is reading 12.8V, gas is dripping from carburetor at about 1 gtt per second, tank is over 1/2 full, and compression test for each cylinder is :
Spark plug reading 1 reading 2
1 110 115
2 110 110
3 110 110
4 115 115

Since I'm in the learning stage, I can't look at that info and tell you what might be wrong. Can someone help out? Thanks!

Once I get the crazy thing started, the real learning starts!! So much to do, so little time.......
 
If gas is dripping from the carb, you flooded it and the plugs are fouled. Pull the plugs and wash them with brake cleaner.

Did you dress the points by running card stock through them?

Will the spark jump 1/4 inch in open air?
75 Tips
 
(quoted from post at 12:46:56 10/16/16) Hi guys.. I have learned a ton from you ppl. I've been lurking in the background reading and implementing but I've finally hit the proverbial brick wall.

I have a 1948 8N that I recently converted to 12V... tractor has all new wiring (including battery (50V 2GA) connections and spark plug wires (stranded copper)). I used this diagram: http://www.myfordtractors.com/12volt03.shtml (EARLY 8N FORD TRACTOR FRONT DISTRIBUTOR?12 VOLT?1 WIRE) which I followed to the T. I have checked all connections to make sure there is continuity and power. Double checked the ground to make sure there is good contact.

I have a new coil that is 12v, 3 ohms giving me total resistance of 4 ohms when the new ballast resistor is added in. I have new points (gapped to 0.025), new condensor, distributor cap, rotor button, spark plugs (AL 437 gapped to 0.025), ammeter, and ignition switch. While checking to make sure I was getting spark at each plug, the bendix on the started decided to explode... so I now have the new rachet style bendix on the starter.

Battery is reading 12.8V, gas is dripping from carburetor at about 1 gtt per second, tank is over 1/2 full, and compression test for each cylinder is :
Spark plug reading 1 reading 2
1 110 115
2 110 110
3 110 110
4 115 115

Since I'm in the learning stage, I can't look at that info and tell you what might be wrong. Can someone help out? Thanks!

Once I get the crazy thing started, the real learning starts!! So much to do, so little time.......

PS.........

Forgot to tell you earlier, your points are set wrong. Gap on the front mount is .015, not .025.
 
Front mount distributor on a 48 so point gap should be .015.
Assuming it is truly a 1948. Sounds like you've done your homework.

I don't wire mine exactly like that diagram, but nothing jumped
out at me that said there was anything wrong with it either.

What does "1 gtt per second" mean? I missed that one.
Still, I have to agree with Bruce that the most common cause
of a "leak" at the carb is flooding while trying to start one.

How did your test of spark at each plug wire end up?
Good blue/white spark that will jump a 1/4 inch gap?
 

"What does "1 gtt per second" mean? I missed that one.
Still, I have to agree with Bruce that the most common cause
of a "leak" at the carb is flooding while trying to start one."

i was scratching my head on that one too, had to look it up. gtt is a medical abbreviation (?) for drops.

when i first got my N, i was thinking i needed to do something about the poorly-fitting air snorkel. silly me, i wanted to clamp both rubber hoses securely. now i have come to recognize the loose fit at the carb as the important feature that it is, as opposed to an imaginary flaw.
 
(quoted from post at 21:21:20 10/16/16)
"What does "1 gtt per second" mean? I missed that one.
Still, I have to agree with Bruce that the most common cause
of a "leak" at the carb is flooding while trying to start one."

i was scratching my head on that one too, had to look it up. gtt is a medical abbreviation (?) for drops.

when i first got my N, i was thinking i needed to do something about the poorly-fitting air snorkel. silly me, i wanted to clamp both rubber hoses securely. now i have come to recognize the loose fit at the carb as the important feature that it is, as opposed to an imaginary flaw.
That's what the sintered strainer is for.
Thanks for the tip on the acronym, I was too lazy to look! LOL
 
Thanks for the replies! Sorry about the "gtt"... I'm a pharmacist.... old habits.....

And I apologize for trying to make you guys read my mind on the carburetor thing too... the one drop per second came from where I was reading on another thread about the troubleshooting involving whether fuel was getting where it needed to get. The drip is when I remove the bolt from the bottom of carburetor.... it is tight as a drum when the bolt is in.... so no leak, but I thought the rate that fuel came out of the carburetor with the bolt out might be a clue or a sign of good/bad fuel delivery.

The gap on the points is going to be fun.... I had a devil of a time just trying to get it to 0.025.... I'll work on that in the morning. And if I ever purchase points again, I'll go with the Blue Streak.

As for the spark, I can only tell you that the light in the tester blinked on and off as the points open and closed... I used the spark plug tester with the light rather than doing the "old sparkie" method. I'll be the first to admit that I'm afraid of the spark.... Most women are afraid of rats, spiders, or snakes..... not me.... it's sparks. Do I need to bite the bullet and do the "old sparkie" method regardless??
 
When you took the bolt out of the bottom of the carb, was the fuel turned on? Because if it was, you should have seen a steady stream.

.015 gap is smaller than the .025 gap you have now so that shouldn't be a problem.

A spark light only tells you that you have spark voltage, not how much. It takes 20kv or so to jump 1/4 inch in open air. So use an old spark plug or buy an adjustable gap spark checker.

But first, clean the plugs, reset the points and dress them and it may well start.
75 Tips
 
No apologies necessary, we just have to make sure we're on
the same page to get things back into working order. :)

"I thought the rate that fuel came out of the carburetor with the
bolt out might be a clue or a sign of good/bad fuel delivery."

If that is the rate of fuel flow with the plug out and the valve on
the sediment bowl open two full turns, then yes, you have a
fuel delivery problem. It should run a steady stream out of there.
Approximately a pint in a couple minutes.

That could be fuel flow to the carb or fuel flow through the carb.
To check the difference back up stream. Is there steady flow
from the line where it attaches to the carb's brass elbow?

If you can get the front mount to gap at .025, you can gap
them at .015 easily. You're not trying to set the gap with the
distributor still on the tractor are you? Much easier to just
take it off and do it on the bench. It only goes back on one way.

I use an adjustable gap spark tester similar to [b:4d5739f117]this[/b:4d5739f117] one.
Less than $10, nothing you need to hold and get shocked.
 
I re-gapped the points to be 0.015. Still no start but I'm waiting for the adjustable gap spark tester to arrive to verify the strength of the sparks.

Since I was only getting 1 drop per second when the bolt on bottom of carburetor is out and gas is open on sediment bowl, I decided to recheck my screens even though hubby replace gas tank, sediment bowl, metal tube and carburetor last fall. I checked sediment bowl screen and brass fitting screen... both are clean as a whistle... (which I have to assume is mighty clean). The key was not on when I was assessing this gas flow... does that impact the results?

As I said... I'm still learning. Hubby threw in the towel after the fuel system replacement events. I'm standing firm. I think the tractor is adorable and I want to run her around the property.... I just have to figure out what each and every doohickey does.....
 
The key won't affect your fuel flow so you're safe there.
If you take the fuel line out of the brass elbow on the carb
do you have good fuel flow out of the line?
If so, you problem is in the carb. Likely a stuck needle valve.
Tapping the outside of the carb with a hammer handle or
a big screwdriver handle may jar it loose.
If fuel does not flow, try it with the gas cap off.
 
I never in a billion years would have tried to work on those points while distributor is still on the tractor, Royce. I just might have chickened out
on the whole thing if that's how the story started (ie, removing hood, radiator, fan, etc). Like I said, I've been lurking for close to a year...
reading and buying stuff.

I read a post in here once that was claiming if you just throw parts at the problem, you'll never fix the problem.... and there is probably a good
deal of truth to that, but I know that it's a great way to learn when you're starting from scratch. I don't plan to replace the entire tractor piece
by piece although is does feel like I've replaced MOST of the peripheral parts... and we added a ROP that our welding friend made for us when we first
got it. And now I know how to check those parts I've replaced to see if they're the problem in the future. Might be expensive learning, but the
local college doesn't offer tractor classes.

Lucky for me and many others out there, nice ppl like you are willing to share what you know, help us with our problems when we don't even know the
name of the parts, and happen to be smart as a whip. That's why I lurked for a while... wanted to make sure it wasn't the blind leading the blind..
HA! I'm gonna try to upload a pic of my tractor.... Her serial number is 8N 50267.
a240361.jpg
 
" I re-gapped the points to be 0.015"

That's good. But, did you dress the points by running card stock through them?

Do you have battery voltage to the top of the coil? (and about half that if the points are closed)

What does your meter say?

If you do have battery voltage to the coil, then the problem is in the distributor.
75 Tips
 
Just got notification on the spark tester arrival....

I did dress the points and I'll see what the meter says at the coil. I'm now leaning more toward the fuel system being the problem since the flow was evidently lacking substantially. I plan to check the flow through the fuel line while I'm out with spark tester and meter.... NOT at the same time of course.... I may be crazy but even crazy has limits....

Thanks for sticking with me!
 

"i'm now leaning more toward the fuel system being the problem since the flow was evidently lacking substantially."

u could possibly have other issues as well, but one drop per second of fuel flow is a BIG problem. until u resolve that, i wouldn't spend time chasing any other potential issues.
 

i forgot to ask, are u working off main (2 turns open) or reserve (all the way open) on the sediment bowl valve?
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top