Spark plug and carburator question...

Do have a couple questions though on possible improvements.

The spark plug closest to the seat (#3 I think) really fouls easily. By fouling I mean lots of gas and debris. New set of spark plug wires would also help I would imagine.

Has been slow starting a couple times. Assumed because it was flooded.

I was using Autolite 216 recommended at Advance Auto. Worked okay. However, in a previous post by Dell and others, you guys recommended a spare set to swap out and Autolite 437.

The new Autolite 437 work great. It was explained to me that the number is only a refernece to the ceramic heat resitance and has nothing to do with how hot they spark.

Could there be a probelm with me using the 216?

What is the difference between the two?

Also, the screw on the carburator is only an idle adjustment and not impacting when running in gear does it?

How do I gauge when I have the idle set correct?

Thanks again to all you guys. You guys are a wealth of knowledge to someone like me who really is not electrically or mechanically inclined.

Black/sooty is rich - fuel fouling.. oily dirty black is generally a OC ring problem... the 437's might help anyway.. can't hurt.. cheap to try...

Soundguy

Heat range refers to how well the heat from the insulated electrode is carried away to the metal housing of the spark plug, and from there to the cylinder head.

In a given engine, a spark plug that is too "COOL", heat range wise, will not get hot enough to burn fouling deposits off, and will foul.

A spark plug that is too "HOT" will get incandescent at the tip, and cause pre-ignition of the fuel charge, before spark occurs, which will cause knock and piston damage.

For a given engine, and also the way you are using the engine, the correct spark plug will be between those extremes.

Typically, a lot of these tractors spend a lot of time putzing around the yard, or whatever, and often are not worked hard for a 12 hour day, as they were when they were someone's main farm tractor.

Therefore, a "hotter" plug works better, because it will heat up enough at the lighter engine loads to burn the tip clean, that's where the "437's" come in.

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Well John..... ...I could suggest you do a "search" of the "archives" of this great N-Board but I won't. Much to the dismay of the environmental bureaucrats, ALL CARBS must be adjusted to match their engine. Each engine and each carb flows (mixes gas) slightly different, but they are ALL ADJUST the same way. MAXIMUM IDLE RPM's, understand? Don't matter, 4-barrel belchfire V-8s, exotic multi-carb 12-cylinder sportscars, 4-cylinder ricerockets, or M/S carb'd N-Tractors; maximum idle rpms.

The M/S is slightly different because it has an adjustable MAINJET, automobile carbs have "fixxed" internal mainjets that are replaceable. But thats another completely different subject and technique.

Both Ford and Marvel/Schebler say to adjust BOTH the SIDE-pointing idlemix needle and the DOWN-pointing mainjet needle to 1-turn to start with. I adjust the down-pointing mainjet to 1-1/2 turns and LEAVITT!!!

I then adjust the side-pointing idlemix for maximum idle rpms, NOT SMOOTHEST idle, max idle rpms. Understand? I then adjust the behind the carb throttle idlespeed screw for a SLOOOooow 400rpms. (ennnythang under 500 is probably close) I do that song & dance 3-times, always adjusting for maximum idle rpms. Understand? My idlemix ended up about 3/8 turn, (last time I counted) yours will be different.

Remember the side-pointing idlemix is BASSACKWARDS; out for lean, IN for ENRICH..... ...HTH, Dell