REPOWER
 

I was sitting here reading some ads, concerning repower engines/replacments. I have a 25' checkmate convincor with a 454/300 H.P. now. I was looking at these 502 MPI motors. Do they come with the computer and wiring complete usually? How involving is it to drop one of these in? Is it sort of like replacing a car engine? unbolt than rebolt with new parts? I know but with busted knuckles! :D

The only way that I would do this kind of an upgrade is with a complete motor, computer and wiring harness from either Mercruiser or from someone looking to get rid of their complete package. That way the entire package is wired from Merc. It will just drop right in your boat. I am not sure exactly what wires would have to be run to match up to the new power. I don't imagine that it is that much. I would get a service manual for whatever year motor you are looking at and check out the wiring diagram. Then just run any needed additional wires.

Don't they also need a return fuel line?

Yup, a return line is necessary for any injected engine (no big deal). My Mercruiser 5.7 EFI came with all the electronics as part of the package. It pretty much plugged into the original (1985) harness. Well worth the big bucks :eek: It's like a new boat now!