base timing keeps advancing by itself...

It has been together around 2 years, and i romp on it continually. I have around 15” vacuum at idle. I put the pink springs in and they helped. Which seems weird, there was no off-idle stumble issue. Smooth transition to partial or WOT. So far, rattling is gone. I think the carb is very lean still. We will see what the 2 stages richer needle does to plug readings.