TT5.9mag said

Sounds to me like you have a lot of transfer fuel and ( [email protected]) and the transition to the mains (off the transfers) is too large of an afr gap. I’d drop the tsr and up the main jet. As a test. What’s the cruise (~2600 rpm) AFR?

Edited to add;
Looking back at your chart I see 14.9 AFR at 2900 and highest vacuum at 17in. You’re definitely on the mains there and lean, I’d step up 4 numbers on the mains and retest.

Click to expand...