Spark plugs

[Bastropian]

Thanks to all I was able to find what was wrong with throttle on my 51 side distributor. I took the governor apart and the steel balls and race were in excellent shape, but the retaining clip that keeps all parts in place was gone. I replaced it, and now the throttle works exactly like it's supposed to. I did not know that the throttle was also a function of the governor.
I was also able to stop the oil leak from governor. It's a good feeling when there are no drips anywhere.

Next issue I have is the spark plugs. They get fouled every time I run the tractor. I have adjusted the carburetor, which is new, the points gap, also new, and the spark gaps (new). But still I can't keep them running clean. The tractor also smokes (black) slightly, which may also be a symptom.
Is there something else I need to be paying attention to in order not to have to take the plugs every time to clean them?
Thanks for all your help.

 

[William Fissell]

Check air supply - ie look at air cleaner? I struggled until I disassembled, cleaned, and reassembled... then life got a lot better.

 

[R Geiger]

I would do a compression check to see what is going on in the cylinders.

 

[Bastropian]

Did a compression test. 3 range between 110 to 120. the 4th is 85. Could this be it?

 

[Bastropian]

I did that. The air cleaner element is clean, and the oil is fresh. I believe that there are no restrictions on the air flow.

 

[old]

#1 use auto lite 437 plug they tend to foul less then others do.#2 check and clean your air cleaner it may be part of the problem. Now as for that one low cylinder compression it is a problem but would not cause fouled plugs across the board. That low reading could be from a number of things. Stuck rings if that pour some ATF in that cylinder and let it sit a couple days. Bad head gasket could also be your problem or a bad valve or set wrong

 

[Jubilee85 (VA)]

Bastropian,

Black smoke? Has your carb been ajusted at all? As others have said, blow by will allow oil to burn and foul the plugs. I too would check the carb ajustment to see if the air-fuel mixture is dead on. Your compression is really good, other than #4....but as OLD said, one bad cylinder would not make em all foul.

 

[Bastropian]

Yes it is black smoke.
I think you're right about the fuel mixture, but other than following the instructions I have found on this site about how to adjust the carb. I am at a loss.
The tractor runs smoothly, with it idling at about 500 rpms. If I go any lower on the idle adjustment, it starts to sputter.

 

[Bastropian]

How much ATF do you add?
Do you add it to all or just the one with the low compression?
Do you leave it in or try to remove it after 2 days?
Do I have to change the oil after this is done?
Sorry for all the questions, but I am not familiar with this procedure.
Thanks

 

[old]

I fill the cylinder that has the problem then in a day or 2 spin it over with the plug out. Ya it will make a mess. No need to change the oil after since ATF is a type of oil just very good at cleaning things up also since most of your numbers are good you only need to do that one cylinder

 

[lha]

First I will say that black smoke is too rich a setting in carb,either from jet needles adjusted wrong or dirty or improper jets internally.This can also be from obstructed intake,but you say the cleaner has been cleaned.Secondly,the spark plugs merely deliver a spark,therefore unless your ignition system is delivering enough current to make the plug spark strongly enough to burn what's in the chamber,they will foul.You need to do a proper compression test:warmed to operating temp and dry and wet,that is with a few tbsp oil in each cylinder to tell if your prob is rings,or valves.Post back after doing a test.---lha

 

[souNdguy]

85 what? wet or dry? you do comp tests dry, then wet then compair the numbers.. this tells you rings/bore or valves.

yer black smoke is too much mainjet most likely

soundguy

 

[Mad Farmer]

when I brought my N the previous owner thought it needed an overhaul, fouled out the plugs after 1/2 hour.

He had water in the air filter which raised up the oil level, sucking it into the carb. I fixed that and get 1-2 years off a set of plugs now with original front mount 6V system. That was 20 years ago.....

check the oil level in your filter