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Mick14

Spark plug question

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Mick14
I just read in a service book that resistor type spark plugs have a more intense spark,if this is true,would using them in these small engines have any real benefit ? i have always avoided them because messing up the neighbors T.V. isn't an issue.

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tec2484
I can't say for sure that this works but a buddy always said that if a engine was flooded, pull the plug wire off the plug so there is a small gap between the plug and wire and you get a hotter spark.

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Mick14
Thats what this book claims,the small gap acts as a resistor and causes a voltage build up and a more intense spark, but is that a good thing with these engines,? will resistor plugs shorten the life of a condenser or the points ?

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Simplicity314
A smaller gap will give you a hotter spark, but a resistor plug won't. I don't know where you heard that. A J8C is used in both two and four cycle engines. In a 4 cycle, the gap is .035, whereas the gap for a 2 stroke is .020. The smaller, hotter gap is needed in two strokes so the plug will fire the gas with oil mixed in it. A less intense spark is need for straight gas. If the spark is too hot you can burn valves. If oil is getting past your rings into the combustion chamber then you can get away with a hotter spark.

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UCD
He is right a larger gap gives a hotter spark. If you have a plug fouling pull the plug wire of and hold it about 1/8th of an inch away from the plug and it will fire and the engine will run. back in the 20's 30's and 40's they sold a spark intensifier that did just that it held the plug wire about 1/8th inch from the plug. The coil has to build a bigger charge to jump the gap.

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ZippoVarga
Thinking if one used a plug designed to pre-load the charge for a hotter spark that it would be to no advantage in an engine that's running as it should. Thats just IMHO. Is there an alternative reasoning for using one in an otherwise good running engine? Perhaps. But I sure don't know what it would be. I have used the ark the gap trick often just to see that my coil is at least hot enough to jump a 1/4-3/8 gap. And let me tell you...insulated gloves dont always insulate. OUCH!! Sean aka Zippo

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