Quote Originally Posted by 36 sedan View Post
I maybe wrong, but wouldn't a lighter spring open the secondaries sooner, which could cause more of a bog. I believe the power valve moderates the fuel for the instant WOT, then the secondary jets come into play. Again I could be wrong, but too small of jets at the secondary will cause a bog at WOT also.

My reading of the plugs (and I maybe wrong), looks like the idle is lean and the timing a little advanced. As tech said adjust your timing and fatten the jets.

Sorry, you're right, must have been a senior moment. Stouter spring since secondaries are tipping in too soon.