Background:
I've recently had an engine swap with a light mileage motor where the shop had preformed a compression test where it was confirmed that both rotors held good pressure. I've had the ignition and fuel system replaced at the same time while the motor was out, but now I'm having issues with cold starts. I thought it might've been caused from my water injection, but even with this deactivated, I continue with the same issue.

Symptoms:
When the engine sits cold overnight it takes about 30 seconds in cranking to get the engine to turn over. Having to pump the throttle to get a little gas to get it to turn over. When it does, it seems to run on one rotor until it warms up. After that I'm fine, the engine runs smoothly.

Help!:
What I'm not sure where to start looking. My Idle control valve seems to not be working properly but I'm not sure if this would be the culprit. My worry is that it may be related to the engine despite the shop confirming the held compression.

Has anyone experienced these symptoms before?

 

Does your engine consume any coolant?

 

What ignition system did you put in? How do your plugs look?

I had a similar issue last spring with mine, it was because my plugs couldn't fire properly (I was running 3oz/gal premix and sometimes my coils just couldn't cope with it all ) If they aren't brand new, also check to make sure your coils are working properly.