Full Force, thanks for posting that. So it looks like this was standard Cigarette rigging for the time period.

the difference is that on FF boat the mech. pump is supplying the carb with everything and the elec is just pushing fuel to the mech pump. what the carb is not ;using is going back to the filter to go again. not really needed to return it but whatever. on yours the mech pump is robbing the elec pump supply and returning it to the filter. whatever the mech pump does not rob then goes to the carb. as MT said, that pump will feed more than you have so as I said earlier just delete the elec and run off the mech pump and see what it does.

If there is a return line after the cab, there is a fuel psi regulator after the carb. I have not heard any mention of this.
But,then again,even though the OP is trying to describe and show pics of what is going on, there are too many things to get in the pic, so I'd need a well drawn out diagram to try to understand and help.

That just looks like a crazy setup. But it looks to me that you have the inlet and outlet on the mechanical pump switched? Never saw a setup like this before

Compression test
Stbd Port
1.) 160 / 150
3.) 150. / 150
5.) 160 / 150
7.) 170 / 170
2.) 150 / 148
4.) 150 /160
6.) 120 / 130
8.) 110 / 150
Water out of 5 & 7 cylinder on both engines

Leak Down Test
Stbd Port
1.) 20% IEC. / 10% C
8.) 80% IC. / 25% C
4.) 80% IEC. / 85% I EC
3.) 35% CIE / 20% ICE
6.) 70% IC / 55% ICE
5.) 25% CE / 30% I C
7.) 80% EIC / 85% IEC
2.) 25% CI / 35% ICE

That's not good..

Damit. That sucks.

It was mentioned that your boat had a survey on it before you purchased it ? If so do you want to give up whom that was and how long you own this boat again. I believe it about 4 months ownership for you ? How much running time did you put on it since you bought it - your boat never ran correctly since day one when you bought it ?. I take it the boat was never test driven nor comp tested ?

Was this a SAMS survey person ?