Plugs fouled

Friend asked me to post this question. M F, 1962 continental engine 4 cyl. Plugs have a soot deposit , (dry) not oiley/wet. ?? When cleaned will operate perfect for quite a few hours and then starts running rough until plugs are cleaned. Cheers, Murray

Dry/black?? If yes one of 2 problems.
#1 he needs to service his air cleaner and dump to dirt/water/ice out and put in new oil
#2 the carb is set to rich or the float is sticking.
Dry black fouled plugs is from t running to rich

I would try leaning it out a little, and switch to hotter plug if that does not work. That is fairly typical if you idle a lot.

http://www.external_link.com/M_S_TSX_Carburetor.html
if this site opens it will give you some info on the type carb and their adjustment

I have an older tractor, 1957 TO-35 with a TSX605 Marvel Schebler carb

I do not know what carb you have but if you have a MS carb this will give you a heads up on adjustment.

http://www.external_link.com/M_S_TSX_Carburetor.html

I know on my Massey 240-S diesel [ I know, no plugs ] the owner's manual says to warm it up at 1200 RPM, and operate it best at 1700 RPM. Don;t like to idle along. Might help you too.

also I use Autolite #3116 plugs they seem to work better than any other plug I have used.

I meant to add this, about heat ranges;

Farmall Spark Plug Heat Range

2014 Autolite Spark Plug catalog
Heat Range Chart page 4-5

18MM thread size
1/2” reach
7/8” hex
HOT rating
 388 Standard resistor plug
 3116 ‘Power-Tip’ Non-Resistor plug
 386 Standard resistor plug
• [gap]
• [gap]
 373 Standard Non-Resistor plug
COLD rating

Each step up equals a 70º – 120º increase in spark plug tip temperature.
Self-cleaning zone is 500°C to 850°C tip temperature.
IF TOO HOT = Possible severe engine damage, pre-ignition, detonation with
racing / high performance engines. .
IF TOO COLD = Possible fouling, possible mis-firing, but no engine damage.


Cross-Reference Chart from Autolite.com
Champion …. Autolite
D10 . . . . . . . . . . . . . . . .373
D14 . . . . . . . . . . . . . . . .386
D14N . . . . . . . . . . . . . . .373
D15Y . . . . . . . . . . . . . .3116
D16 . . . . . . . . . . . . . . . .386
D16J . . . . . . . . . . . . . . .386
D18Y . . . . . . . . . . . . . .3116
D21 . . . . . . . . . . . . . . . .386
D23 . . . . . . . . . . . . . . . .388
D6 . . . . . . . . . . . . . . . . .373
D77V . . . . . . . . . . . . . . .373
D9 . . . . . . . . . . . . . . . . .373