but Autostart has varied little ...
That's the problem... According to my manuals, they do differ greatly....
GE: after the
3rd start attempt the engine is motored for two minutes and the starter is shut down. It has a 20 second lightup detector for the first start attempt, then 15 and 15 seconds for the 2nd/3rd attempts. In between start attempts there is a 30 second cooldown timer.
RB: Has two start attempts. After each failed start attempt (due to no lightup) the starter is kept running until the cooldown temperature is achieved (which may be no time at all if there was no lightup). It has a 20 second lightup detection timer on the first and second start attempts.
PW: runs for a total of 5 minutes
Assuming the PW is simply starter runtime based, the GE, in theory, comes close to the PW's 5 minutes, but on the RB (assuming no temperature rise) the start could be aborted 2 x 20 seconds after initial fuel on.
Cheers