8N Running Rough -- Air Cleaner clogged?

[SmittyN]

I just bought a 8N/2N combo (8N Engine & front axle / 2N sheet metal & Tranny-Rearend) tractor today. I'm new to the N's. It was running pretty rough with lots of black smoke. I leaned out the carb and that cleared up most of it. It's still running a little rough. If the air cleaner is dirty, could it cause the mix to still be too rich? I have new H12 sparkies and I'm getting good blue spark.

Any suggestions for a new "N" guy?

Thanks!
Smitty

 

[Jerry/MT]

The Marvel-Schebler carb that is used on most N"s is a "presure balanced design" that has a fuel bowl that is vented to the carb inlet passage and so the fuel/air ratio is insensitive to the air cleaner restriction. However the restricted airflow will limit the power. Are you sure the choke is not partially on?

If you were running rich with the new plugs and then adjusted your mixture, your new plugs might be carbon fouled and that may be causing the problem. How are your wires? Are they copper core ignition wires? If not, they should be.
Do you have the correct firing order?

Hope this helps

 

[old]

Well first off pull off the oil cup on the air cleaner and see if its #1 not full of water/dirt. #2 has the right amount of oil in it. Also with it off start the engine and see how it runs. If when its off it runs well then the air cleaner mess may need cleaned or if has dirt dubber nests in the down tube. Seen it many times and dirt dubber do a good job of clogging things up
Hobby farm

 

[souNdguy]

Jerry and Old are giving you good advice... check the carb and the air filter cup.. .. air cup is a fast test..

soundguy

 

[SmittyN]

Soundguy, Old & Jerry:

Thanks for the advice and your replies!

I will check the carb, air filter assembly and choke.

The tractor does seem to be underpowered. It also reacts slow when throttling up. Checking the air cleaner assembly will be the first order of business.

Are there any adjustments on the throttle linkage? I looked last night, but didn't see any. I did see that one piece of linkage appears to be bent. I have to move the throttle off the quadrant plate to get full RPMs. Given it's 8N/2N heritage, I'm wondering if they intermixed throttle linkage pieces? Does anyone know if the 8N and 2N throttle linkage pieces are interchangeable?

The carb is new. I'll have to check on the make & model. It is dripping gas from the drain plug. The gas shutoff is in the "shut off" position. I'm going to pull the gas line off at the carb to see if the gas shut off is working properly.

About the choke, does it have a return spring on it. I have to hold the choke out or it springs back in. It does this with the engine off or when I'm rolling it over. I tried to look last night, but it connects on the back side of the carb and I could'nt see very good. (I only had a flash light.)

If my understanding is correct, the plugs wires are in the correct firing order (1-2-4-3)?

The current wires on the tractor are automotive. I have new plug wires from TSC. The guy there said they are what he uses on his 8N. I had not put them last night before posting. I will double check to see if they are copper core and if so get them installed.

I seem to have come across something else that strikes me as odd. The Engine is an 8N-B model with the right side distributor. However, I have a magneto instead of distributor system. Did this engine model have a magneto option?

I ordered the 2 service manuals, Parts manual and Operators manual for the 2N from YTC last night. I realize today that I need to get some 8N manuals as well. I guess I was a little more tired than I thought.

Thanks for your suggestions and advice guys. It is greatly appreciated.

SmittyN

 

[Hobo,NC]

I would not hesitate,,, clean the element in the filter if fot nuttin more just so I know its clean,,, its over 50 years old and time for maintenance,,, they don"t stay clean for ever,,, The element for a 8N is EZ to git out,,, unroll,,,clean and reinstall,,, the 9N,2N I am not sure of,,, I just cleaned the lower element on a Ferguson,,, stopped slap up,,, no wonder it had to B roped and pulled back in every time it got used,,, I had to burn the crud out,,, wash"n would not git it clean,,, would not even touch it. This should b on the top of every ones list to do
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[Jack - Illinois]

Yes the choke has to be held on if working as it should. I like it that way because you can't accidently leave it on!
Not knowing the prior history of your tractor, it may have some stuck rings. Pulling out the plugs and adding a couple of tablespoons of ATF or Marvel Mystery oil in each cylinder and leaving this stand over night may help. Also a compression check would show stuck rings.
Having a magneto on it may be that this engine came from some equipment that was hand cranked to start. This was common on seasonal equipment which meant the owner didn't need to worry about a battery.

 

[SmittyN]

Hobo & Jack,

Thanks for your reply and the advice!

The engine spins over easy and I'm not getting any blue smoke. I have some Marvel Mystery Oil (wonderful stuff) in the garage and I'll give it a treatment.

I don't know what either (8N or 2N) air filter system looks like so I don't know which it has. In any event, I'm soon to find out. Taking it apart is next on my list.

I'm in Mid-Michigan(30' degree winters and 78' summers on average). I've read alot about engine oil, but there seems to be no clear consensus on what to use. I think one or two guys said they use 10w-40 or 15w-40 detergent oil. I don't think I have an oil burner or loose rings. Think this is a good starting point?

Thanks!
SmittyN