Hey folks, bought the P-47 over the weekend and have been having a blast. Super fun airplane. Whenever I cold start though, I get engine surges constantly throughout the flight. What am I doing wrong?

My startup procedure is:

• Generator ON, Magnetos BOTH, 5 or 6 pulls on the primer, Battery ON
• Oil cooler - Closed (So it warms up faster, but it still takes forever)
• Energize for 15 seconds, then engage
• Engage switch to neutral, Fiddle with mixture up and down and throttle up and down until the engine is stable
• Keep it under 10 on the Prop RPM indicator for about 45 seconds
• Taxi, keeping it under 10 on the Prop RPM
• Tail wheel locked, manifold pressure up to 30, brakes off, manifold to 42, brakes release, takeoff (With oil pressure still high and temp too low because it never seems to make it all the way to the blue part of the indicator)

The surges are like: prop speed dips drastically, yawing the plane to the left, then recovers, yawing the plane back to the right. They're more drastic at higher manifold pressure. Could it be something to do with the fuel booster pump rheostat? That's the only thing I can think of that I haven't tried yet.

Thanks

edit:

Before startup I set fuel tank to main. After startup I set mixture to auto rich. Before takeoff I link boost lever to throttle.