The position of that ring does NOT MATTER.----Just line it up so the 4 screws go in.----Are the breaker points absolutely clean , with zero resistance when closed ?
???---438559 fuel pump.----Available all day long in almost every boat repair shop !!-----Not sure why these simple pumps are so mis-understood.----Not sure why folks are so confused.
It could be that there is an issue with crankcase compression.----It is the PRESSURE that drives these pumps.-----How did motor behave with the VRO pump ?----Did you find something wrong with old pump ?