8N 1947

[classic478N]

Having trouble getting my 1947 8N to run correctly.
It ran good when I parked it this last spring and summer when I went to use it was stalling and backfiring
It runs good at an idle however if you throttle up over third throttle it stumbles real bad and backfires very loudly and then dies. Also will not run without the choke out and least quarter of the way or more.

I have a side mount distributor and 12 volt system.
I do not use the tractor a lot so I thought bad gas so I removed all the old gas added fresh gas.

I have put on a new filter and settlement bowl assembly under the fuel tank and put a new fuel line on from tank to carb.

Put a new carb on and removed the air filter connection from carb to make sure the air cleaner was not plugged.

I put new coil points plugs condenser dist cap plug wires rotor. I gapped the points and plugs at 025

My coil has internal resistor so it is direct to my ignition switch and have 12v at the coil with ignition sw turned on.
Nothing I have done from the list above has helped.

Not sure what to try next any help would be welcome.

 

[Farmer Dan]

(quoted from post at 19:27:04 01/04/19) Having trouble

Need to clean the carburetor. Happens a lot if you let them set to long. Having to use the choke to make it run is a good indicator.

 

[Royse]

You've got the year confused on the tractor, but that shouldn't
matter too much since you say it has a side mount distributor.
You've replaced the carb, but have you checked fuel flow through
it? Pull the drain plug, turn the gas on, catch it in a jar. It should
fill a pint jar in two minutes or so. Inspect it for dirt or water.
Also check your firing order, 1-2-4-3 CCW and check the timing.

 

[classic478N]

(reply to post at 19:37:58 01/04/19)

My carb is new. I had the fuel tank a few years ago cleaned and the guy put some kind of liner in it so it will not rust. I believe the system is clean. Thanks for the fast response.

 

[Robert1234]

I would check for air leaks at the carburetor connection and the intake manifold , spray small amt of starter fluid on connections at carb and manifold to engine if it revs up you have a leak

 

[R Geiger]

Might see how it runs with the gas cap off. If it was lined most likely the vent hole was plugged. new carb or not I would remove the plug in the bottom of it and measure the fuel flow. Should fill a pint jar in about 2 minutes more or less.

 

[classic478N]

I pulled the line off carb and drained gas tonight. I do not know if this is normal. It would run out and stop trickle then run out again.
I pulled the gas cap thinking it might be holding the pressure and it
did not change the gas flow.
So i ran a line from carb to another tank but the tractor ran the same. I did not find a good picture of the distributor cap the shows
where 1 is. I did move the wires on the cap after i tried all the other stuff. I have The 1 second position going clockwise from the wire stud to coil.
Was wondering why the year is wrong the serial number on the left side of the block is 30803.

 

[HFJ]

(quoted from post at 23:27:52 01/04/19)
Was wondering why the year is wrong the serial number on the left side of the block is 30803.

sidemount distributor was first used in mid 1950, iirc. could u have missed a digit in the serial number?

 

[Royse]

The side mount distributor didn't come out until mid 1950.
Not a big deal, probably just can't read one of the numbers.

It is not normal for the gas to stop and/or trickle. There is
something wrong with that. If loosening the gas cap didn't help,
I think you have something in the tank restricting flow. Does
your sediment bowl have the screen on top of it inside the gas
tank and are you only opening two full turns for normal operation?
Opening it all the way open gets you into the "reserve" which is
quite often plugged up and could cause flow issues.

The position of #1 on the distributor cap can be changed by
inserting the distributor in the engine at a different location.
Turn the engine by hand until #1 piston is on top dead center,
or better yet, 4 degrees before TDC and see where the rotor cap
points. The cap tower that it points to is where the #1 wire goes.

 

[classic478N]

I thought that too when I started looking on the internet for the year using the number 30803.
I wire wheeled lightly so i had a clean area and rechecked the number but will check again in the morning.
Will also try the leak down from the carb like you suggested and spay carb cleaner near the gasket to check for air leaks.
Take care.

 

[Royse]

The serial number should start and end with a diamond or a star.
The numbers in between the symbols should start with 8N.
If that's not the case, maybe you have a replacement engine,
industrial engine, or some other replacement. It happens.

Here's the location of the serial, compliments of John Smith.

 

[shelbym71]

download the 75 tips and follow them they will save you a lot of headaches and money

 

[shelbym71]

http://www.yesterdaystractors.com/articles/artint268.htm

 

[Tim PloughNman Daley]

You have a few issues going on. First, forget about the s/n. It's either a front mount distributor or an angle mount. What 'filter' are you talking about on the sediment bulb? There are three in-line filters, two in the sediment bulb, one on the brass elbow inlet on the carb. Next, there is no internal resistor in the coil. Who told you that? Why was the carb replaced? Simply replacing parts without knowing the condition of the existing part is not logical. New stuff today is often junk and the OEM parts were designed to be rebuilt over and over. You cannot assume any new part today is good to go out of the box either. If you didn't open up the carb and check float and then Main and Air Idle Mix settings, you may have more problems than before you started. You said you set the ignition pint gap to .025", which is good. Did you remove the side inspection cover and then time it? The procedure is in the original 8N Operator's Manual and the I&T FO-4 Manual. Finally, you need to verify the wiring is correct. "Stalling and backfiring" can also be caused by an electrical short. I don't suspect a fuel issue, most likely an electrical issue. Get the carb and fuel system right, perform fuel flow test to carb. Then get into electrical. Don't be creating any sparks if fresh gas is present for safety reasons. You can go thru wiring using a correct 12V diagram and applying NO power to the system first. Once the danger of igniting any fuel has passed, start with timing the engine.

Tim *PloughNman* Daley(MI)

 

[showcrop]

Check fuel flow as Royse and Rgeiger told you. No short cuts!

 

[classic478N]

(quoted from post at 19:58:33 01/04/19) I would check for air leaks at the carburetor connection and the intake manifold , spray small amt of starter fluid on connections at carb and manifold to engine if it revs up you have a leak

I did this today and did change the RPMs.

 

[classic478N]

(reply to post at 07:07:51 01/05/19)

was talking about the filter that sticks up from the sediment bulb. I pulled the fuel tank today and removed the sediment bulb. It was all clean. I turned the tank upside down and dumped into a clean container and checked the tank inside. It was clean. I pulled the plug off the bottom of carb after I reinstalled the tank and filled with new gas. After 2min had about 2qts of gas coming out.
I replaced the carb because I have had issues before with it. The new one I just installed out of the box no adjustments and does make it idle better however it does the exact same thing little over third throttle it starts to run bad.
I did not do anything with timing yet. I have checked the wiring. One question I had was the coil I bought has internal resister and in the now 75 tips it says You always need the OEM ballast resistor with a front coil even if you use a 12 volt however the wiring dia says 12v system does not need it?

 

[W_B]

replaced the carb because I have had issues before with it. The new one I just installed out of the box no adjustments and does make it idle better however it does the exact same thing little over third throttle it starts to run bad.
I did not do anything with timing yet. I have checked the wiring. One question I had was the coil I bought has internal resister and in the now 75 tips it says You always need the OEM ballast resistor with a front coil even if you use a 12 volt however the wiring dia says 12v system does not need it?[/quote]

With a new carb you have just swapped one problem for another. Get your old one rebuilt but not a hard job to do yourself.

Again, why do you think your coil has an internal resistor? If you have a 12 volt square coil all you need is the OEM resistor and NOT that ceramic one in addition. I assume you are looking at JMOR's diagram, it clearly shows the OEM (the original one that came with the tractor) resistor and no other. I assume also you checked your wiring against the diagram, if it follows that everthing will work.

Just did the 12V conversion and rewiring to my own '48 8N.

 

[classic478N]

(reply to post at 20:48:59 01/19/19)

irst off thanks for saying with me on this. I live in mi. and it’s been too cold to work on my N consistently. I’ll have order a rebuild kit likely take some time on that. The coil I bought round can style said in the description for 8n with internal resistor. I have a wiring dia found on line. JMOR’s wiring dia. I looked through the above posts and might have missed it can you show me how to find it and I’ll compare them. Thanks again you guys so great when I posted my issue I thought I might get one response in a few days or so and in a couple hours it seemed like I couldn’t keep up with you guys. I’ll keep plugging away at it. Take care all. High of 12 today tonight -9. Jeff