Spark plug reading

So a jump/change of 2 in heat range?
Transfer slots...I'm "pretty sure" :rolleyes: they're close to square. To be honest, I may pull carb to chk T-slots but that won't be for a week or so.

Bewy said

[1] At idle, how much transfer slot is showing?
[2] Unless this engine is going to see WOT for minutes, not seconds [ in a boat or circle track racing ], I would using NGK 4 heat range. You will get a better idle & better mileage, & no down sides.

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Weak ignition is a good point. I was battling/exorcising electrical demons and there was a LOT of idle time to go with the exorcism.

Hysteric said

Weak Ignition.

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