Rewiring 64640A10 Control Box on 1977 Merc 1150: Tach Plug Question

[kck8385]

I am installing a new external wiring harness on my 1977 1150. I am about to wire the new harness into the control box and have noticed that the old harness had the brown tachometer wire directly connected to the male tachometer plug (the 3 pin male side that mounts in the box). The existing brown wire has the insulation crumbling all the way to the plug so I would like to replace it.

Can I buy a new male tachometer plug harness for the control box so I can splice in the brown from the new external harness? I have searched but have had no luck.

Thanks,

Kevin

 

[jimmbo]

If it were me, I would just paint the bare spots with some liquid neoprene

 

[kck8385]

Jimmbo,

I thought about that but by time I get finished splicing the new brown from the external harness to the old brown from the existing plug all the wire insulation will be gone. Every time I move the old brown wire more insulation falls off.

I guess if I don't want to liquid neoprene the entire remaining portion of the old brown wire my options are to find a plug or run new wires directly from the control box to the tachometer.

Thanks again,
Kevin

 

[Chris1956]

Replace the tach wire or cover it with spagetti or shrinkwrap. Not sure I understood your question on new male tach harness. You need three wires with ring terminals on one end and then solder the other end to tach signal, ground and ign accessory wires.

 

[kck8385]

Chris,

Sorry if my explanation is confusing.

What I have is that the following.

-Existing tachometer connector (male plug) that mounts in the control box has 3 wires. White and black attach to screw terminals just in front of the connector. Brown goes all the way back to the engine.

Question: What is the best way to connect the brown from the new external harness to the old brown coming out of the tachometer connector in the control box?

Thanks,
Kevin

 

[Chris1956]

Well, that is a bit clearer. How about using a solderless butt connector? When I use them for marine connections, I pull the insulation off the butt connector, slide some shrink wrap onto the wire. Flux the wires and crimp them to the connector. Now sweat solder the connector and pull the shrinkwrap over it.

 

[kck8385]

Chris,

I'll give that a try. I am still going to have to liquid neoprene or shrink wrap the old brown coming off of the connector because all of the old insulation will be gone by time I move it around a few more time.

Thanks again,
Kevin