Engine Swap 99 to 87 Merc 3.0 No power when key is "On"

[KingMarine]

Hello there, long story short.. I have a 2000 party barge pontoon that the Mercruiser 3.0 had to be swapped out of. We replaced both the engine and outdrive with a functional 87 Mercruiser 3.0. The primary issue is that the engine will turn over and start while it is cranking, however it seems to lose all power when you let the key rest in the ON position? I did notice that the connectors match up but one wire is missing in one of the connectors. In preliminary pinout lookups I believe this wire is not related to power or ignition, perhaps audio warning alarm? Any help is appreciated.

 

[achris]

:welcome: aboard.

If you're not losing instrument power in the ON position, then that symptom is usually an indicator that the resistance wire (in the engine harness) has failed...

Chris.........

 

[dubs283]

lanyard switch on remote

 

[Scott Danforth]

use a DVM and start at the key switch and start looking where you loose voltage starting at the key switch.

I have gone thru 2 key switches on my current boat since 2011 because the "run" terminal was worn out

 

[achris]

...I have gone thru 2 key switches on my current boat since 2011 because the "run" terminal was worn out

Well, you're just using your boat far too much. Just stop it!

Chris......

 

[Scott Danforth]

Well, you're just using your boat far too much. Just stop it!

Chris......

I also quit buying the cheap plastic switches..... current one is brass

 

[achris]

I also quit buying the cheap plastic switches..... current one is brass

:thumb: (cheap rarely means best value)

 

[Bt Doctur]

wire nuts never wear out

 

[KingMarine]

Thank you for all the input. This last weekend had to work on my wife's truck. Will be back out there Saturday trying to figure out the culprit.