There may have been some other factors involved, but his morning we started two back to back pulls without changes.
The oil started at 155 degrees the first pull and 159 degrees the second and there was a 9 HP difference. Changed spark plug wires and made two more pulls starting with the oil at 160 degrees and then 166 degrees and we saw an 11 HP difference.
Is that conclusive? I don't know. It's only four pulls. Maybe I'll keep better track from now on.
