Motor rewire

[aburke120]

I was caught in the rain the other day working on the motor so I jumped in the boat while it rained, and while there I had thoughts of taking the MerControl off and seeing what was in it. Taking the screws out had the entire control coming off where it was mounted, and not coming apart like it would have a 2 piece top and bottom, so l put the screws back in, and went back to the motor. will the merControl come apart?
I had the switch box and control box confused, thanks.

 

[Chris1956]

Switch box is potted with epoxy. No serviceable parts there.

MerControl splits into two halves. There should be 2 SS screws to hold it together.

 

[aburke120]

thx chris
What's in the switch box anyway, is it just a big terminal strip, or is there other things inside it to make it special?

 

[aburke120]

As the rain continued over the weekend I was looking at the wiring diagram of my motor, and noticed that it included a diagram of the mercontrol. On the forward part of the control were three wires and a plug labeled tach connector. I looked under the dash (that's another rats nest) and found that a red wire and a black wire coming from this tach connector were connected to the positive and negative buss that powers everything on the dash.including the running lights for the boat. and bilge pumps, live well pumps, That's the reason in an earlier post I stated that the switch on the dash and the switch on the mercontrol need to be on for things on the dash to respond. Today's not raining so I recharged my battery and will hook it back up to the boat, and see what happens. Didn't see if the tach was hooked up, but it shouldn't matter now. The wires that went to the + and - buss under the dash had spade lugs plugged into the tach connector.

 

[Chris1956]

You are not supposed to power anything but instruments from the plug on the MerControl. The ign switch is pretty robust, but bilge pumps can use some current, possibly burning it out.

There is a 3 wire molded plug that connects to the MerControl. Not sure where you could get one these days...

I would disconnect everything from the MerControl plug, and remove all wires on the battery, except the two motor cables. KISS.

 

[aburke120]

I did unhook it when I found it yesterday. there was an old radio in the dash that I removed, found the dashboard, if that's what it's called, broken so I took the switches out. they were all brittle and most broke when removed, they were rocker switchers and the only one that rocked was the nav light. the rest were broken. can't see where anything else powers the buss. No luck on the motor turning over, have to go over the wiring again.

 

[merc850]

Wire all the accessories to a terminal strip under the dash and run separate +, - wires directly to the battery thru a fuse or circuit breaker of adequate amperage; you can wire a tach into the harness plug if the brown wire from the 4 terminal side is moved to one of the yellow wires on the rectifier (NOT the red one). The control handle has to be in N to start the motor, turn the key and move the handle slightly back and forth to find where it will start.

 

[aburke120]

Nothing going on yet, still fighting mother nature, supposed to get warmer this week I'll get back at it. thanks

 

[aburke120]

Still fighting with mother nature, 23 this morning, heading for a high 41. might work under the tarp on the control box. This boat has a key switch on the dash and a key switch on the control box, is this normal. Also the motor has an external hydraulilc pump to control the tilt and trim of the motor, wires for the T&T pump are wire tied onto the big lever on the control box. Going to put some power on the pump to see if it spins.

 

[aburke120]

anyone know if there are any sponsors that sell or can get a motor harness for me. Harness number is 414-2770. thx

 

[GA_Boater]

anyone know if there are any sponsors that sell or can get a motor harness for me. Harness number is 414-2770. thx

iBoats sells the CDI 414-2770 harness - https://www.iboats.com/shop/catalogsearch/result/?q=414-2770

 

[Chris1956]

I would do a google search on the OEM part number for the wiring harness. When I looked for one, some years ago, there were many sources and prices.

 

[aburke120]

Chris 1956, thanks for the Google tip, have one coming in the mail. I'll get back to it after it gets here.

 

[aburke120]

got the new harness this week, cold again going to wait for the sun. I did mock up the new harness, rang all the wires from the old plug pins to what's left of the wires going out to the motor. Confused as to the directions given with the new plug. Directions state to not use the white wire going to the switch box, but there's a place there for it.
Are the fuel line hook ups all the same on these old motors, When I get to the point of trying to start this motor I'm going to use a 6gal tank,

 

[merc850]

The white wire supplies + 12v to the switchbox as in diagram; if you want to make sure it has 12v connect a VOM or small12v light to the wire and turn the key on this will energize it, turn it off and it will be dead. This starts and stops the motor.
Any large Mercury bayonet fuel fitting will work.

 

[aburke120]

Thx Merc850, I'm learning more terms everyday. Looking at the harness, and where it goes doesn't look like rocket science. Every connection has a post and a nut and washer. I got a angle plate with with the harness it has a couple of holes in it, and a slot on one side I'm guessing this holds the harness in place. Got a fish fry to go to this afternoon, fresh caught walleye and perch. temps only 36 right now, headed to 45 for a high and 25 mph winds. Don't think I'll be working on it today. Later.