Mercruser 3.7 488 wiring help

[Blentz17]

I inherited a 93 Petit Manan bow rider which I am in the process of restoring. The boat itself is in pretty good shape, but the electrical is a mess. When I got the boat the main engine harness was cut along with the harness running from the trim/tilt to the throttle. The throttle and trim/tilt are going to be replaced so I’m not to worries about figuring those wires outs. But I do need help with figuring out where these wires I have a pictured go. Whenever I have restored boats in the past I haven’t really had to mess with the electrical, so this is all fairly new, have not been able to find a good wiring diagram for this motor

The first question is where does this gray “hose” go which is coming from the speedometer

Second: this second stand of wires is independent of the main engine harness, and the boat has an additional harness which is still connected to the engine which feeds most of the engine components, I'm not sure where this set of wires go ( I included a closer picture of the wires for reference)

third: these set of wires are also independent of the main engine harness and I can’t seem to find where they go, I thought they may connect to an additional solenoid as the red wire looks like it may connect, but I’m not sure as there’s not an obvious point on the boat

Last, so I said of wires are coming off the throttle harness I’m not sure where they go either.

If anyone has a good wiring diagram let me know.

 

[Blentz17]

So I know the first one now of for the Speedo, still need help with the rest

 

[alldodge]

Motor side

Helm side

 

[alldodge]

Moved to Merc section because while it is wiring, it's problem wiring the motor

 

[Blentz17]

Moved to Merc section because while it is wiring, it's problem wiring the motor

Ok so that harness is still connected to the boat this is an additional harness that runs from the engine to the console area.

 

[nola mike]

6 pics, could you label them better? Also can't tell which wires are original color from the plug vs. spliced with a different color.
"Feeds most of the engine components"- which components?
Pic 2, looks like the main harness from the engine to gauges
Pic 3, is there a plug on there? Looks to be boat specific, direct wiring to bilge pump maybe
Pic 4, wires on the left are to throttle trim switches or on the other end to the trim pump
Pic 5/6 again looks to be boat wiring, pink maybe fuel sender, same yellow and black as in pic 3?
You should only have the main harness plug feeding engine components. Another plug feeds trim. Assuming points system? You may or may not have a separate starter slave depending on test. 488 does not, 3.7 does (90 should be 3.7)
Also your wiring is a bit different because of the stator/voltage regulator. Some extra orange and y/r that may or may not be in use. Does the engine have an alternator conversion?

 

[Blentz17]

I’m pretty sure I figured everything out, I’m going to reinstall the gauges and harness tomorrow and see how it goes

 

[ROY WILLIAMS]

I’m pretty sure I figured everything out, I’m going to reinstall the gauges and harness tomorrow and see how it goes

I was the soldering connector wires and the shrink connector ...

 

[Blentz17]

I was the soldering connector wires and the shrink connector ...

 

[Blentz17]

I got the main engine harness hooked up and it appears to be working as im getting the signal from the trim. As the gas tank is currently out of the boat, the fuel which was originally on full went to empty. The other gauges are all at "zero" because the motor is dry (no fluids), i will be tackling that tomorrow. the component harness was so corroded that I am going build a stand alone harness and connect it to a stand alone house battery.

 

[alldodge]

Could go custom
https://www.hardin-marine.com/p-13230-custom-mercruiser-style-engine-harness.aspx