Twin 454's and the engines run great. I wouldnt say it starts super hard but it doesnt start easy and I usually have to pump the throttle on each 4-5 times as well. Im looking for these things to start on first turn of the key or at least easier. I was thinking maybe some carb cleaner in them. It't not electrical I dont think. I have new batteries this year and they read fine, also have new slave solenoids.

Could be fuel pumps leaking back fuel or carbs not holding fuel. Have carbs ever been rebuilt? kits are cheap.

i dont know. It shouldnt have a fuel pump since its carbed right

How do you think the fuel gets from the fuel tank to the carb then??

yes it has a fuel pump on it, but its mechanical VS an electric pump like a EFI boat would have.

dirty carb could be the issue?

ok thats what I thought. It seems the carbs either arent holding fuel or are dirty. What part would you rebuild if they were holding fuel

Are we talking hours between starts or days or weeks

My 525sc's sometimes take 8+ pumps when starting cold. Normally the rest of the day is fine, but the initial start is a challenge. my old 454 mpi was turn key & go.

carbs tend to do that if you leave boat sit for a week or even a few days I think fuel evaporates out of bowls and depending on your carbs you may not have chokes ( mine are hp series no choke ) b ut as was said above once they start mine will start easily they rest of the weekend , so I am not sure you have a problem unless somthing has changed or you are having trouble after they are warmed up

If they're losing fuel could be the needle seats. To check after shut down remove the air cleaner and look down the throttle bodies. You
will see fuel dripping if they are leaking. It is a common problem. When I had carbs I always kept a spare or two. Also may want to make sure your timing hasn't changed. I've seen that years ago in my ski boat.

Do a total rebuild on both...