Dorianjeffries505
Member
So I gaped my plugs to .030 and it seems to not run at top speed anymore why is that? But it still don't like the real cold weather tell it warms up. Then it just runs ok and will idle at a stop light but only of its warm.
Spark plug gap size on a aluminum head
- Thread starter Dorianjeffries505
- Start date
Too big of a gap can cause spark suppression at high RPM. The wider the gap, the more energy it takes to jump that gap. In high heat and pressure conditions, like those of a combustion chamber right before ignition there is a much higher electrical resistance in the atmosphere that makes it harder for the plug to also jump that gap.
Then the coils have something known as dwell time, or how long it takes for the system to apply voltage to the primary windings. If you start reaching or exceeding the minimum dwell time of the coil the voltage through the primary windings starts to drop off and you see a decrease in secondary output because of the reduced field being created, aka less spark strength. Since 2 strokes fire twice as often as 4 strokes the dwell time can become more critical, something that usually isn't an issue with most 4 stroke small engines.
Simple Terms/TLDR
Wide gap + weaker spark at high rpm = spark blowout.
There is a reason most of us run and recommend a .25 gap. I have even run a .20 gap before.
Dorianjeffries505
Member
I tried 25 and nothing was better so I dropped it back down to 20 will see how that works for me. But I really wish I had a better coil any requested ones I should go with?
