Finnaly have some miles on this new motor so I decided it was time to dial in the secondary side. After a couple of rod and hanger changes with the tension spring set at 3/4 of a turn after the spring makes contact with the lever I still had a stumble. hmmm ok the flap must be opening too soon(right common problem) add a little more tension and the problem got worse. So what I did was back off a 1/4 turn at a time until it has no hesitation at all. runs great! I get back to the garage and switch out the test air cleaner for the stock one and notice the air valve is open a little; no spring tension. Taking all the tension off the spring is what made this engine perform. What up here?
Air valve still held closed by the vacuum pulloff? Maybe try more spring tension, larger orifice in the pulloff.
Since you made some changes to the secondary metering, is it possible that the metering was too rich, causing the need for additional air before the rods rose? Check the metering rod hanger cam for wear, and retry at 1/2 turn. It may also be possible for the changes made to have caused a problem in the adjustments. It is also possible for the stumble to be caused by a fouled plug, and the testing cleaned it. Just foood for thought...
