Ford 8N mystery

Jonesy54

New User
Hi, all...new guy here, working on a 1952 8N, side mount dist., still 6 volt - had been sitting awhile so I replaced: dist. cap & rotor, plugs & wires, points & condenser, fuel screen and fuel line to carb., NEW M/S carb, also rinsed out fuel tank and all new gas and installed new glass bowl assembly.

Starts right up by holding choke out, but when I let go, she dies. If I hold choke 1/2 way, she'll run.
What am I doing wrong? any help is appreciated. We're in between snow storms and would like to get her running.

JC
 
You might have better luck if you post in the N-Fords further down on this forum. But: have you pulled the plug off the bottom of the carb to assure you have good flow to the carb? Where are your power adjust, and idle needles set on the carb? I don't know where they should be set, but if it takes part-choke to run, try turning your big power adjust needle another 1/2 turn out and see if it makes a difference. If not, there's probably some crud at the bottom of the carb bowl stopping the gas from going past that needle. Time to clean all the passages in the carb. steve
 
better follow your fuel flow from the tank to make sure you have full flow entering the carb. if so ,then you better check your carb adjustments. have you checked the main setting??? kinda the first thing to do if you know you have full flow of gas entering a new carb, plus set the carb. and before that is the ignition set to spec's. nobody ever gives info on what they have set things to. just replacing them means nothing. many a tractor i get running good with out buying any of that stuff. that is not a sarcastic comment as people seam to think here at times, its fact.
 
here's a picture of the fuel circuits in the MS carbs, from 'How to Rebuild MS Carbs-Route 249
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That complicated mess at the bottom right is where the junk usually stops up the gas flow.
 
I understand, Red what you are saying, but he disturbed a bunch of stuff upstream of the carb, and may have a whole lot of junk in that new carb. And I, for one, don't think you are being snarky in your posts. I think your posts are always 'to the point, no BS', which might be a little blunt for some. steve
 
New carb is very likely to be made in the land of almost right and of course it isn't right. I'd have the old carb rebuilt and have a good carb instead of a China made wrong carb
 
ya. its unclear when the carb was installed, as its made to appear as he came with a hand full of parts and put them on cause the tractor was sitting. problem as i always say, lack of all the info. and before hooking fuel line to the carb its a good practice to flush the line first any time and all the time before hook up. it only takes a spec of dirt from the dirty line and fitting to give problems.
 
Jonesy .... sounds like it's been your tractor for a while. Not that it makes a big difference now but ......

1) Was it running decent when you last ran it?
2) How long has it been sitting for?
 
I general any carbureted motor that requires additional choke to run has the fuel supply blocked somewhere. Choke reduces airflow and carb can run with less fuel.
The question in this instance is where is the fuel reduced at. Could be carb, fuel line etc. Several of you have provided useful info where to look. So Im not going to get into that.
 
This from the dearly departed Dell Golightly: ''It ain't how many turns that count in adjusting a carburetor. Each carb and engine is uniquely different. That's why thar's them handy-dandy fiddle screws on your carb. Can you tell the difference between the idle mixture and the main jet mixture screws? Can you tell where the low speed idle set screw is? Can you tell which governor rod connects to the carb throttle shaft? Ford owners manual sez to set BOTH the idle mixture and the main jet to 1 turn. Well that works on a new carb and a new engine. I don't think your tractor qualifies. Therefore, I suggest 1-1/2 turns for both the idle mixture and the main jet. After you get your engine started and fully warmed up (about 15 minutes), adjust the idle mixture for MAXIMUM RPMs, not maximum smoothness, understand? MAX IDLE RPMs. Tractor idle spec is 450 RPMs which is awfull slow to our ears. If your carb is anywhere near being right, you can do it. Now then, goose your throttle. If engine doesn't respond, enrich the mainjet 1/8 turn. Do it again. You may have to go out 2 turns on the main jet but no more.
Learn how to read your sparkies color. After idling for 15 minutes, pull a plug. It should be a light tan or gray color. If it is sooty black you're too rich. If it is clean white, you're too lean. But most important, adjust idle mixture for MAX RPMs. Then, go plow or do heavy work for a few minutes at high RPMs and pull a sparkie and read the color. That will tell you how well you've adjusted your main jet. From the black art of adjusting carbs.......Dell
 
If you have done everything suggested to the carburetor and still have the same problem, clean and adjust your ignition points.
 
The job of the choke plate is to allow for enriched mixture during cold, first start operation. Once the tractor and carb are up to temp, the choke should not be needed to maintain running. In summary, your stoichiometric ratio of air to fuel is too lean.

With the engine running and the choke partway on, let it warm up fully, try not to go too rich with the choke and foul the plugs. Get the tractor up to above 1200 RPM, may have to do this by sound if there's no tach. This will put you in the main metering range. Reduce the choke as much as possible just to keep it running.

At this point, start turning your main mixture screw out, that is anti-clockwise. The engine should pick up speed. Reduce choke as you go. Keep doing this with the mixture and choke until the tractor will run without choke at all(hopefully).

Stop now and remove one plug. If it's black and fuel fouled clean all plugs and put them back in. Start up the tractor and get it running WOT. The governor will not let it overspeed. At WOT, start slowly turning the main mixture screw in. Note when the engine looses RPM, and begins to surge. From that surge point turn the mixture screw out 1/4 turn.

Reduce the engine speed to idle. Set the idle speed to book value at 450-500RPM. You are now on the idle mixture circuit. Turn the idle mixture screw in until you note the speed decrease. It may be very slight, but it should decrease in speed as the mixture goes too lean. From that reduction in speed, open the idle mixture 1/4 turn.

From idle, advance the engine speed quickly. The engine should respond and not bog down. If it bogs down, adjust both idle and main mixture so that there is a smooth engine speed advance when the throttle is advanced. Check your plugs again, clean as needed. That should be it.
 
When your tractor sets idle for a long time, best to get it started first and running B4 you start yanking things off and replacing them. Until you perform true root cause problem solving methods, you are just guessing and parts probably don't need replacing anyway. Yeah, many 'fuel issues' turn out to be electrical issues and vice versa. And just because your battery is 6V do not assume you are wired correctly for the 6V/POS GRN setup. Wiring PICTOGRAM by JMOR is below. Note that lights are often incorrectly wired, on both 6V and 12V setups, and are a major reason for shorts and non-starting issues. Lights were never a factory feature; always a dealer optional accessory. When troubleshooting electrical, always first disconnect the lights and the battery. Next, you say NEW M-S CARB... is it a cheap Chi-Comm made clone or a real Marvel-Schebler TSX 241-B Carb? Rebuilding the OEM components is always the best method for these vintage machines, as they were engineered to be. New stuff is mostly junk. If you installed one of the clones, did you just put it on out of the box? You do know that there is no QC in Cheena, they do not preset to specs or even test anything built in Cheena, right? Setting the float to 9/32 (1/4 will suffice) is important. The newer style Needle & Float Valve has an extra clip and must be set correctly. The Main, Air Idle, and Throttle/Speed Mix adjustments should be to initial specs per manual. First order is to perform the Fuel Flow Test with a cold engine. Fail? Go thru usual possible causes and then R&R'g the carb correctly if needed. If carb passes fuel flow test, leave it alone and move on to electrical. Next, When your tractor sets for a week or longer idle, the 2nd best investment you can make, having the ESSENTIAL MANUALS is 1st, is to get a good float charger, DELTRAN BATTERY TENDER JR is very good, and keep battery at optimum charge so it is ready to go when you are. A basic garage/shop trickle charger won't do the same thing. Get battery tested for specific gravity with a hydrometer or better yet, at a local shop, under load on their special test machine. Next, replacing all the distributor parts, otherwise known as a tuneup, requires it is done correctly setting points to .025, setting the timing first static per manual then with a timing light at 4 degrees BTDC on flywheel via the inspection cover; and firing order is 1,2,4,3 CCW. Going thru the entire wiring system first is required B4 turning that ignition key. A visual at first will tell you condition: Starter Motor is a 3-Wire unit with a RELAY(Solenoid); Generator is a 3-Wire/2=Brush 20 AMP, A Circuit Unit amd must have the belt tensioning device on it; and the correct Voltage Regulator. If you want, I rebuild OEM M/S Carbs and have TSX-241 on my shelf now. Your ESSENTIAL MANUALS are required but if you don't have, here some pages to help you get started. Start with these suggestions.

FORD & M/S TSX CARB DIAGRAMS:
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NEW STYLE NEEDLE & FLOAT - NOTE EXTRA CLIP:
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FORD 8N ELECTRICAL, AFTER S/N243844:
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Tim Daley(MI)
 
First of pull all the parts out of the trash if you still have then and clean them up to put back on.
 

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