What's the serial number?
Takes more then just a CPS for it to fire.
What are "all the electrical checks"?
Was a spark gap tester used?
Was the old motor running before reman installed?
You ran the motors for about 10 minutes with no water and all you did was rotate it by hand to verify the impellers are ok. Now there is a problem and ya need help. ok pull the sea pumps and let us know what you find
Item 20 in the pic above is just a plastic barbed fitting. The fitting has a reduced ID so when stat opens the water flows more freely to Mans instead of the elbows. Cost about $4
https://www.mercruiserparts.com/bam/subassembly/31752/13884/210
Connect the jumper on DLC
Turn key ON, move throttle handle to WOT and back to neutral
Turn key OFF wait 20 seconds
Turn key ON and see if it cleared. No codes in a MEFI will be code 12 only
Do agree with Scott BT made a nice distribution housing out of copper.
Guy at my dock has replaced 3 of them before he decided to just leave the drain plug out of it during winter. All those tubes can clog up and can drain more later.
There will be some exchange of water in the Mans when the stat is open, just not as much. They should not get real hot, like no hotter the the stat temp
That's the manifold drain. Only one of them were drilled thru for the pipe plug. The plug along with ones on the motor block are removed for winterization.
The big issue is your current thermostat housing. As you have seen the housing will not pass water until the stat opens. If you keep the current housing you have to reinstall the Tee fitting and extra hoses.
This is what was there including the Tee from the single drain
Could change to...
