(800) 853-2651
SHOP NOW

My 8N runs rough after warm up.

R

Robert G. Miller

New User
My 8n runs rough after warm up. Ive replaced all
ignition parts and rebuilt Carb in hopes of fixing
the problem. After it cools down completly it will
run. If it has not cooled down it will spit and
sputter after you put it in gear and try and move
tractor. It will always start right up put wont take
a load on engine unless you let engine cool down
then runs fine until warm up.
 
6v or 12v? Front or side distributor?

W/ all those new parts, did you set the timing?

What did you set the point gap at?

Did you double check the firing order & plug wires? (1-2-4-3, CCW)
75 Tips
 
More info would help us help you better. Could be a coil going bad or a manifold leak or even the valves needing to be adjusted because as the engine gets hot the tappet gap could be closing up causing it to not run well because valves are not closing as they should
 
Its a 12 volt front mount. I don't remember the gap off the top of my head, but i did it according to specks. I have done some reading on others with this problem. I am beginning to wonder if its in the head like you mentioned. What do I do to check the head?
 
" What do I do to check the head? "

Rather than jump on a possible but seldom seen problem, you would be better off checking the simple & more likely possibilities.

Like firing order & timing.

did you set the timing on it?
75 Tips
 
So then front mount so did you try another coil on it?? If it runs ok for say 45 minutes then starts to cause problems good chance it is the coil going bad
 
Do you have a propane torch?? If you do when it starts running bad take that torch and wave it around the manifold area. DO NOT light it. It it smooths out when you do that good chance you have a bad manifold gasket. Also check you spark when it starts doing that and make sure you have a good blue/white spark that jumps a 1/4 inch gap or more
 
RGM..........there are 4-common runtime issues with the weird 4-nipple front mount dizzy.....
1) runs fer about 1-min and quits; restarts inna'bout 5-mins; BAD condenser, NOT yer problem
2) runs fer about 5-mins and quit; restars inna'bout 5-mins; CLOGGED in the tank fuel filter, NOT yer problem
3) runs fer about 15-mins and quits; restarts inna'bout 30-mins; BAD weaksister ignition switch, NOT yer problem as stated but could be
4) runs fer about 1-hr and quits; restarts after about 4-hrs of cool down time. Sound like yer problem??? BAD squarecan ignition coil. Unfortunately, once the insulative tar melts, it will always melt inna'bout 1-hr. Time fer NEW COIL. .......Dell, yer self-appointed sparkie-meister
 
Ah but Dell if you read all of his posts he done did the new coil thing and that did not fix his problem. Sorry I do respect your posts but some times you do need to read all that has been said. I to asked about the coil and he answered me with it was new. Yes could be a bad new coil form the land of almost right which could well answer it all
 
When did this behavior start? Is it possible the muffler is the problem stopping gas flow when hot? Did it run like this before converting electric system to 12V? If you pull out choke a little when it "spits & sputters" does it run better? Have valves been ground or adjusted just before this behavior started?
 
It has always been a 12 volt system since I have owned it. I will try a new coil. Maybe the one I bought was bad.
 
Sure sounds like a coil. But, it could be that it is not getting enough voltage once the (balast?) resistor warms up (12 volts). You might want to jumper around the resistor after it warms up.

Would it technically be a bad coil just because it requires a bit more voltage? I don't know.

Then again maybe you don't have a ballast resistor in the circuit at all.
 
You must log in or register to reply here.

Similar threads

K
8n sputters and dies when on a hill
Replies
13
Views
481
Dan
D
U
8n Steering box
Replies
7
Views
436
Tim PloughNman Daley RIP
T
C
JD A no spark after warmed up
2
Replies
23
Views
723
wore out
wore out
D
1948 8N steering
Replies
13
Views
544
Dan
D
F
801 runs rough when timed
Replies
17
Views
764
FarmerBlair
F
Tractor Parts Tractor Manuals

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.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top