Just remember, an owners manual would have had a list of servicing dealers in 1977 and a generic drawing of the boat indicating the pointy end is the bow and the end with the outboard is the stern.
not sure what information you are looking for.
measure fuel pressure. lines running from pump to carb are steel, so you will need the test fitting. you should have 3-5 psi from the pump.
fuel pressure will tell you if there is an obstruction
you are comparing gen 2 blocks and gen 4 blocks. like apples and yo-yos
here is some light reading https://forums.iboats.com/threads/complete-history-of-the-4-3-liter-with-casting-numbers.693935/
remember, the balance shaft has bearings that are oiled by the oil passages. you cant just remove the balance shaft. the only thing you can do is remove the gear driving it. then, you do not get all the benefits of the balance shaft and the motor vibrates like a dog passing a peach pit
draw...
Primer bulb is not allowed on an I/O
Stop throwing parts at boat. Not sure why you changed the carb
Look at the ignition system. Have you serviced the points?
first, welcome aboard.
next, most boat manufacturers do not have owners manuals like cars.
at best, you need to get the manual for the motor and drive (it has the important bits of wiring schematic)
