Repowered from 2 to 4 Stroke

[Reel Kahuna]

I'm repowering from a 1991 pro V 2 stroke to a 2004 4 stroke both 150 hp.

The existing 2 stroke has the OEM tach and Speedo gauges, 703 control with the main wiring harness, and oil tank (that I won't need)

What can I use from the 2 stroke and what will I need (including part numbers) to buy for the 4 stroke?

[rodbolt17]

your going to need the tach, the tach/warning/trim harness or the correct harness adapters and make sure the 703 box has 10 pins in the main harness.
partnumbers someone else can supply.
the 91 pro V 150 used round connectors on the tach and trim/warning harness and the F150 uses square connectors.

[Reel Kahuna]

My existing 2 stroke tach (red/yellow/green, oil/trim/temp) and speedo are the old style so I ordered a new 4 stroke digital tach.

I don't think I'll order a speedo being that all the info it contains are also displayed on my Lowrance LCX113c HD.

In my search, I found a used 703 control box with the 10 main harness. There are two group of wires coming out of the box.

The 1st has three wires Light Blue, Light Gray, Red that connects to the up/down trim ****on. I'm thinking that these wires are connections for a remote trim switch (?).

The 2nd has four wires and based on the color code the Yellow is key "On 12V, Black is ground. Dark Green is Tach and Red (is currently capped) is constant 12V (?).

If this is not the case, please correct.

[rodbolt17]

wire colors are correct.
your still going to need the harness for control box to tach and engine to tach.

[Reel Kahuna]

wire colors are correct.
your still going to need the harness for control box to tach and engine to tach.

The 703 I bought has the 10 pin harness connected to the box.
I ordered a new tach with wiring harness that's due for delivery this Friday. I'm assuming these wires connects to the motor? I guess the best thing is for me to gather all the parts, swap motors then see what's missing