A friend also ran a 40FP RJL or Davis converted - probably Davis. We lost him over a year ago...
He also used a starter for the engine, which had been left at last running settings. I don't think he primed at all, just relied on the natural intake flow at starter RPM. First start took several seconds, later starts were quicker if there was any heat remaining in the engine.
The engine ran well, reliably and with great power. I think he used heavier-load props, which diesels handle with ease... 11-6 or larger..
He did shear a shaft at the crankweb on one: probably it got too wet and hydraulic locked on him with the starter cranking.
MORAL? Don't use a starter on a flooded diesel... Now, where have I heard that before....?