8N runs great for 15 seconds and then sputters

reluskie · Sep 24, 2016

I have a 1949 8N that was rebuilt a little over a year ago. It was converted to 12V at the time of the rebuild. It has a side mount distributor.
It has developed a new problem, the engine sputters and back fires (maybe once, not a lot) after it runs for about 15 seconds. I was able to limp it back to the garage but barely. I have changed the points, condenser, plugs, plug wires, distributor cap, rotor and I blew air through the fuel line to see if plugged - no issue there.
I have a spare carburetor so I swapped that, same condition. I'm ready to roll the tractor down the driveway and make sure it's lined up with the swamp in front of my house!
I checked spark on all the plugs, getting spark. The points were set a .025" with the gauge that came with the points. The coil is NOT getting hot (at least not that I can feel). I'm stumped on this one and don't know what else to check.

HFJ · Sep 24, 2016

do u have an inch of gas in the tank, or a tiny bit less? sounds like what happens when u try to pull fuel thru a plugged reserve pickup.

pull the drain plug on the bottom of the carb with the valve on the sediment bowl open. it should fill a pint jar in 2 minutes. thanks to a suggestion from one of the gurus here, i replaced my plug, which was mangled, with a petcock.

don't use it as landfill quite yet

reluskie · Sep 24, 2016

Tank is full. I did pull the plug and was getting decent flow but don't remember the exact amount.

I did stop by the local dealers and looked at new ones, I'm thinking if I threaten that I'm going to replace her she might come back to life

R Geiger · Sep 24, 2016

(quoted from post at 15:33:45 09/24/16)
Tank is full. I did pull the plug and was getting decent flow but don't remember the exact amount.

I did stop by the local dealers and looked at new ones, I'm thinking if I threaten that I'm going to replace her she might come back to life

When you pull the plug you really need to let it flow for a while. It should fill a pint jar in 2 to 3 minutes.

One of mine was doing the same thing and the main fuel stand pipe was mostly plugged.

Maineman · Sep 24, 2016

I'd suspect bad gas, bad coil, bad ignition switch or, bad wireing.
And I wouldn't replace anything till you find the problem.

Bruce (VA) · Sep 24, 2016

If it'sa 1949, it would have a front
distributor.

Check the firing order. 1 2 4 3, CCW.

See tip # 13. As soon as it stops running
use an adjustable gap spark checker to see
if the spark willjump 1/4 inch.

Remove the bolt in the bottom of the carb.
Let it run for 30 seconds.
75 Tips

reluskie · Sep 25, 2016

You are correct, the distributor is on the front, not the side. I guess I was thinking front side :shock:

I'm heading out of town for a week so will attempt the fuel flow test when I get back.

I filled three 5 gallon cans of gas, one of them went into the 8N, the others in my lawnmower and chainsaw. I'm 99.9999% sure it's not a bad gas problem. I have a spare gas can off a lawn mower, maybe I'll try to bypass the gas tank completely to see if that solves the problem. I'll post my results when I figure this out or I'll post a picture of my new tractor..... (and show a picture of the 8N in the swamp)

Bruce (VA) · Sep 25, 2016

" The points were set a .025" with the gauge that came with the points."

That's the likely problem; point gap on the front distributor is .015, not .025.

Re-check the plug wires, 1-2-4-3, CCW.
75 Tips

reluskie · Oct 14, 2016

(quoted from post at 05:42:27 09/25/16) " The points were set a .025" with the gauge that came with the points."

That's the likely problem; point gap on the front distributor is .015, not .025.

Re-check the plug wires, 1-2-4-3, CCW.
75 Tips

Since my original post, I put in a new coil, set the point gap to .015, checked the fuel flow - filled a 2 quart canning jar in about 2 minutes, checked the compression - all cylinders are approximately 120, rechecked the firing order - it is correct, and swapped out the carb for the "extra" one I had in the shed.
Fired it up tonight after setting the gap, it took right off for about 5 seconds and then back to spitting and sputtering and back firing. I did notice more smoke than usual.

Totally frustrating. I have to believe it's something simple but I am absolutely baffled on this one.
The only thing that looks funny to me is the location of the #1 plug, it's on the side of the engine instead of closer to the radiator. I was thinking the #1 should be up front.
One other thing I did do over the past two weeks, I contacted several new tractor dealers....... They have some great incentives going right now, just hate to spend a ton on a new tractor.

reluskie · Oct 14, 2016

the fuel flow was in a canning jar, probably 1 quart not 2 as stated.

GB in MT. · Oct 14, 2016

[b:99e0144bad][i:99e0144bad]

reluskie........ You say...."The only thing that looks funny to me is the location of the #1 plug, it's on the side of the engine instead of closer to the radiator. I was thinking the #1 should be up front."

If this is what you were thinking,......How did you re-check the firing order, as per what Bruce Va. told you to do?????

Here is a picture, of what/how, to set the firing order......: trace each plug wire from piston to distrib. cap plug-ins!!!!!!

Gary[/i:99e0144bad][/b:99e0144bad]

reluskie · Oct 14, 2016

(quoted from post at 16:59:01 10/14/16)

Firing order is correct but I was thinking the wires may have gotten 180 degrees off.
Thinking this might have been the issue, I pulled the cap and spun it 180 degrees, it wouldn't even start with the cap spun 180 degrees so I believe I eliminated that possibility.

reluskie · Oct 14, 2016

I'm going to make a Youtube video of it and post the link on the site tomorrow, maybe something will jump out that I'm not seeing.

Royse · Oct 14, 2016

"I pulled the cap and spun it 180 degrees"

I think we need to determine for sure what tractor you're
working on. You can't spin the cap 180 degrees on a front mount.
The cap on a front mount looks exactly like the picture GB
in MT posted including having the coil mounted on top of it.
You shouldn't be able to do that on a side mount and get it to
seat correctly either, but we'll get to that once we know.

Since front mount and side mount point gaps are different, it
makes a difference in how we can help you.
Can you post a picture of the right side of the tractor and of
the distributor?

If not, please tell me this - sitting in the seat, what side of the
tractor is your alternator on? My guess is it is on the left side.
I'm assuming you have an alternator since you said it is 12V.
If not, which side is the generator on?

Dell (WA) · Oct 14, 2016

Reluskie........FYI, a bad condenser generally show up in about 5-secs. And surprizingly enuff, they are generally highly reliable. ...but... yer points arn't. Me? I'd pop the cap and stick the corner of $1-bill (cheap) between the points and pull. Oh yeah, the 4-nipple front mount is designed to have the points (0.015) replaced on the kitchen table. Just unbolt the 2-bolts and walk. After replacing the points (0.015) and polishing the INVISIBLE CORROSION from between the points with yer $1-bill, just finger start the 2-bolts and install the rotor. Now twist the rotor until the OFF-SET tang fits the OFF-SET slot in the camshaft. Now tighten the 2-bolts and re-snapple yer capple. Last point, keep yer itchy-twitchy fingers off'n them handy-dandy carbie tweek'ems. Adjust yer down pointing mainjet to 2-turns and LEAVITT!!! Adjust yer side pointing idlemix fer FASTEST idle, NOT smoothest idle. Understand the difference? The side pointing idlemix should be 1/8-1/4 turn. Finally, replace yer FLOODED sparkies. Recommend AutoLite 437's gapped 0.025. Don't throw yer flooded sparkies away, just clean and dry them, one-atta-time in HOT runnin' engine. And save'em fer the next time. (and there will be a next time)....... HTH, the amazed Dell

reluskie · Oct 15, 2016

Great advice, I'm going to change the condenser AGAIN. I've changed the points and condenser twice. I believe my carb settings are 1-1/2 turns, I'll try 2.

Bruce (VA) · Oct 15, 2016

[i:e9b602d5cc]" I pulled the cap and spun it 180 degrees"[/i:e9b602d5cc]

That's impossible w/ a front distributor.

It's almost impossible w/ a side distributor because of the notch in the cap.

[b:e9b602d5cc]Please answer Royse's question[/b:e9b602d5cc].

We need to know for sure if you have a front or side distributor.

[i:e9b602d5cc][/i:e9b602d5cc]

Bruce (VA) · Oct 15, 2016

The pic is a front distributor.

It is on the very front of the engine, below the fan.

Does your distributor look like this?

Unless you can tell us which distributor you have, we can't help you to get it running.

75 Tips

Bruce (VA) · Oct 15, 2016

This is a side distributor.

75 Tips

Royse · Oct 15, 2016

(quoted from post at 09:52:29 10/15/16) This is a side distributor.

75 Tips

A valiant effort sir. Unfortunately, there are parts to re-replace.

reluskie · Oct 16, 2016

(quoted from post at 18:32:31 10/15/16)

(quoted from post at 09:52:29 10/15/16) This is a side distributor.

75 Tips

Click to expand...

A valiant effort sir. Unfortunately, there are parts to re-replace.

This is the one that's on my tractor.

Bruce (VA) · Oct 16, 2016

Good,.

You've learned 2 things so far: you do NOT have a 1949 8N and you do have a SIDE distributor.

Next.....

Have you replaced the condenser?

Have you re-set the gap on the points to .025?

Did you loosen the distributor to set the timing?

Have you physically traced each plug wire from the cap to the corresponding plug? (# 1 plug is closest to the radiator). Firing order is 1-2-4-3, CCW

Do you have the little clip underneath the rotor on the shaft?

Is the rotor firmly set on the shaft?

Is the cap firmly set on the distributor w/ the notch in place?
75 Tips

reluskie · Oct 16, 2016

(quoted from post at 05:56:07 10/16/16) Good,.

You've learned 2 things so far: you do NOT have a 1949 8N and you do have a SIDE distributor.

Next.....

Have you replaced the condenser?

Have you re-set the gap on the points to .025?

Did you loosen the distributor to set the timing?

Have you physically traced each plug wire from the cap to the corresponding plug? (# 1 plug is closest to the radiator). Firing order is 1-2-4-3, CCW

Do you have the little clip underneath the rotor on the shaft?

Is the rotor firmly set on the shaft?

Is the cap firmly set on the distributor w/ the notch in place?
75 Tips

color=darkred:d66b2ce6a5][/color:d66b2ce6a5][color=red:d66b2ce6a5][/color:d66b2ce6a5] Changed the condenser twice, reset the gap from .015 back to .025, have not messed with the timing - figured it was working where it was before all this started, physically traced all plug wires
THE CLIP UNDER THE ROTOR: Mine has been missing for a long time, didn't even realize it was missing. I will pick one of these up.
The notch on the distributor cap has me puzzled, I'll go out and look for that, don't recall seeing one.

As far as the age goes, I remember looking up the serial number a few years ago and could have swore it was a '49. My dad always indicated it was a '51, maybe he was correct....

Bruce (VA) · Oct 16, 2016

The cap is notched to keep it from being installed 180* out.

Put the cap on correctly w/ the notch set on the tab & then re-check your wires for the firing order.

I'm surprised the tractor ever ran w/o the rotor clip.

You might as well buy 2 of them; they are easy to lose!

reluskie · May 11, 2019

3 years later I'm finally closing out this post. I didn't push the tractor into the swamp but seriously considered doing so.... I purchased another 8N and decided to use the one one I couldn't get started for parts.
After sitting for about a year, I decided to strip it down and rebuild it from the ground up. When removed the gas tank and started to remove the cap and coil I noticed the wire that goes from the coil to the distributor cap was "scuffed" on the bottom side of the wire - it was not visible when looking from the side of the tractor. The scuff was causing the distributor to short out and stall. I spend hundreds of dollars on parts trying to figure out what was wrong with that tractor and it ended up being an 8" piece of #14 gauge wire is all it needed.....
I finished painting it and put it back together, it looked like a million bucks when I sold it (Unfortunately not for a million bucks).

Royse · May 11, 2019

It's been a while, but thanks for following up!
Your issue turned out to be something that many others may see.
I'm glad to hear you finally figured it out and got it fixed.
Couldn't let it win!

8N runs great for 15 seconds and then sputters

Member

Well-known Member

Member

Well-known Member

Member

Well-known Member

Member

Well-known Member

Member

Member

Well-known Member

Member

Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Member

Well-known Member

Member

Well-known Member

Similar threads