Spark Plug

[Cacti_Ken]

What is the difference between the Autolite 2243 and 2245 spark plug.
Is the resistor only in the 2245?

The vendor sold me 2245's for my M38.

I see they are already black with soot after running only a little while, Maybe thirty minutes.

What spark plug do you guys have?

I took my engine back to the rebuild shop Friday for him to get the oil leak fixed. So we'll see how that comes out I guess next week.

[wesk]

Heat range - 2243 colder and 2245 hotter. The 2243 is correct for the L134. The 2245 is correct for the F134 in the M38A1 and the M151's odd motor. If you're fouling plugs with the 2243 then the hotter plug will sometimes help out and let you defer needed maintenance. The black soot on your new 2245's in your fresh built engine indicate the carb is a little rich or the air flow into the engine is restricted. A little rich is good though for a fresh engine.

[Cacti_Ken]

Well I noticed on the 2245 plug that it had "Resistor" ingraved on it. So I figured it was a cooler plug.

[wesk]

Both are resistor type plugs.

[LoboMike]

I had a similar experience. Consant quick fouling and finally found that "new fuels" had "eaten" one of the diaphrams (metering IIRC). Went to John at Midwest for new kit to get the new diaphrams and have had no problem since.

HTH

[Cacti_Ken]

Carburetor might need a little tuning. pump and carburetor are new rebuilt items. Only way I no how to tune a carburetor is turn the mixture screw in slowly until engine rpm starrts to drop then back it off until rpms begin to rise., then turn just a hair more out. And see how it functions.