The fast then almost stopping is common for systems where there is some decent compression in the cylinders and the starting system is weak. And too much base advance in the ignition timing can make that worse. Retard the ignition timing 4-5 degrees and see if it wants to start better when hot. If it does, then you have found a limit on base timing. If not, then it is the starting system and/or the cylinder pressure... which could be made worse by valve issues.
What do have for a negative connection to the battery and from the chassis to the engine?