I'm not sure if anyone can help without seeing schematics, but I'll try anyway.
My IMP has twin 1991 EFI 5.7 Mercruisers. The starboard engine is at the machine shop getting rebuilt. Turns out the block is cracked. So while it's there, I want to startup the port engine to see if that block is cracked.
With one engine out, and all of the wiring disconnected for the starboard engine, I'm wondering if it would do any harm to the port engine if I start it up (protecting all the loose wires and making sure nothing shorts of course).
I guess my concern is around some vague memory of disconnecting a battery from a running engine and it damaging the alternator, or some such thing. Anyway, I thought I'd ask if anyone knows if this might cause damage to the electrical system. It's not a complicated boat, just your typical 1991 power boat with 350 twins. The port engine is all wired, it's just the starboard side that has the harness disconnected.
Thanks in advance!