Fuel starvation ?? 15 HP Evinrude 1978

She will run for an hour flat out then die but and I have to pump the
fuel bulb.....pull the starter twenty times and she wont start and the
plugs are bone dry. Have stripped the carb twice and this appears to
bring her back to life, but have also stripped the fuel pump to find
one spring should it have two ?

Fuel lines are OK and she has new plugs, compression is good. Is there
a knack to setting up the main jet 25 turns in seems to work but the
tick over is now difficult to achieve. Did tick over perfectly before
??

Have blown through all the ports on the crab with fuel from a syringe
so I am off to get some carb cleaner and strip her down again but I
think I may have two problems, pump and carb.

Any comments greatly received.
JG