N11YC plug

I have a 2510JD with N11YC plugs, the #1 cylinder misses I have new plugs wires cap rotor points. #1 fouls the plug there seems to be plenty of spark out the end of the plug wire and plug. This has been an ongoing issue if it gets warm enough it may start running on all four. Today (zero degrees) I let it warm up for 20 minutes before moving it but wouldn't jump to all 4, just use it that way. Is there a hotter plug to put in that might help with the problem as it is just the same cylinder that keeps bothering or do I need to pull the head. Thanks

(quoted from post at 19:12:40 01/15/22) I have a 2510JD with N11YC plugs, the #1 cylinder misses I have new plugs wires cap rotor points. #1 fouls the plug there seems to be plenty of spark out the end of the plug wire and plug. This has been an ongoing issue if it gets warm enough it may start running on all four. Today (zero degrees) I let it warm up for 20 minutes before moving it but wouldn't jump to all 4, just use it that way. Is there a hotter plug to put in that might help with the problem as it is just the same cylinder that keeps bothering or do I need to pull the head. Thanks

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You might start by doing a compression test to see what you have.

Myself, I would try using NGK BP6ES plugs and see if that helps

When everything you try doesn't work, pull the head and grind the valves on the bad cylinder.
Before you do that,

Run at full speed. Then use IR thermometer to measure exhaust temperature. Both exhaust temperatures should be the same.

Switch spark plug. Measure exhaust temperatures again. If same cylinder has less exhaust temp you have limited spark plug problems.
Last resort grind valve.
Report back.

As long as it runs on all four when warmed up it has enough compression to fire. Make sure you don't have a intake manifold leak on that cyl and put in a hotter plug like a number NC8YC. Can only lose price of one plug.

If the plug is truly oil fouling, then yes, a hotter plug or a non-fouler will help.

But any plug will foul if the cylinder is not firing for any reason. Could be weak spark, low compression, cracked head or leaking head gasket, or improper mixture.

Once a cylinder has been run misfiring for an extended time, the cylinder will be sooted up and oily. It may quickly foul a new plug until it cleans itself up after a while of successfully firing.

Be sure there is good spark at the plug end of the plug wire.

Check the compression, adjust the valves if that hasn't been done lately, and inspect the valve train while there. Look for broken springs, valves not fully opening (flat cam), bent pushrods.

Be sure the thermostat is working properly, and the engine is coming up to operating temperature.

Carefully check for vacuum leaks, especially since this is a cold weather problem. Look for a manifold gasket leak since it seems to favor one cylinder.

Back to the original question, yes there are hotter plugs. The 11 is the heat range, Higher numbers run hotter, 11 is mid-range, you can go up to a 12, 14, or 16. If you determine the problem is oil fouling, you can use a non-fouler, it is a threaded spacer that moves the plug out of the splash zone and causes the plug to run much hotter. Should be used only as a last resort, and you might want to go back down to a colder plug for that one.

Have a look at this chart, see what best matches the results you are seeing.
Plug Chart

x2

My mind was going backwards on the heat range of that spark plug. Higher number is hotter.