Mercontrol conversion - 75 Merc 1150 to 83 Merc 50 HP

[jbrown7891]

Thank you for advance for the wealth of knowledge on this site. I am trying to convert my Mercontrol (black and blue) from the wiring for my old 1150 to the 50 hp I just purchased.

I can't seem to find a wiring diagram for the Mercontrol and the 8 pin connector for the 50 HP. I have a complete 8 pin harness, boat does not have T/T so that is not an issue. Trying to determine what wires from the 8 pin harness should be spliced to what wires in the old 1150 harness... Here is what I have come up with so far from piecing together a 50 hp internal wiring diagram and a 1150 internal/external diagram that I found.. but still not 100% sure this is correct:

Pin 1 - Black-Yellow - Mercury Switch Hook-up - ? Brown wire from 1150 ?
Pin 2 - Doesn't look like it's used, but not sure what to hook it up to in the Mercontrol
Pin 3 - Doesn't look like it's used, but not sure what to hook it up to in the Mercontrol
Pin 4 - Black - Ground / Starter Solenoid - ? Black from 1150 ?
Pin 5 - Gray - Rectifier - Unsure what correspondes from 1150, seems they only use Red
Pin 6 - Yellow-Black - Choke Solenoid - ? Gray from 1150 ?
Pin 7 - Yellow-Red - Starter Solenoid - ? Yellow from 1150 ?
Pin 8 - Red - Rectifier / Starter Solenoid - ? Red from 1150 ?

Any diagrams or quick reference would be greatly appreciated. Thank you.

 

[Chris1956]

Re: Mercontrol conversion - 75 Merc 1150 to 83 Merc 50 HP

You are pretty close. We have the new motor wiring colors on the left an the old harness wiring colors on the right, right?

Black/yellow is the ign killer wire. Connect it to the salmon or orange wire. BTW - Your '75 merc 1150 did not use this wire, but it will be present in the boat harness.

Black is ground. Connect it to the black wire.

Grey is tach signal from the rectifier, connect it to the brown wire.

Yellow/black is choke. Connect it to the grey wire.

Yellow/red is starter solenoid. Connect it to the yellow wire.

Red wire is for unswitched +12VDC. Connect it to red.

You missed the Purple wire for Ign accessories. Connect it to the white wire.

The last wire may be tan. It was used for the overheat alarm. The 1150 harness will not have this wire.

 

[jbrown7891]

Re: Mercontrol conversion - 75 Merc 1150 to 83 Merc 50 HP

Exactly what I needed... thank you.. you guys on here are awesome.