1976 Mercury 650 thunderbolt 65hp power loss/speed

Ok so i figured out my problem with the cylinder not fired thanks everyone for the help, but now im having other problems. So I took it out for the first time in a while last week, and it was running fine in idle but when I would run 3/4 throttle for about 2 min it would do about 40 mph and then bog out and act like it was starving a fuel. So I took the carbs off and cleaned them out and found out the floats were set wrong so I put them back to what the books specifications are.

So here is the problem i took it out today after i set the carbs back to there proper set up. and it was lacking the get up i noticed. When i got it out to the open water it was going like half of its normal speed, and had half its tork it was taking alot longer to to start the plane and just didnt have the get up it had a few days before. I messed with the carbs air screws at the dock and took it out again and it still didnt run at the normal speed. so i started looking at the throttle adjustment but its fine i think it going all the way to full throttle but still no power.

any ideas on the problem

I would start with the basics: ensure the fuel tank vent is open, the tank may vent enough even with it closed to idle and operate at part throttle but not at wot (a worn gasket or poorly sealing cap could be allowing some venting). Check the fuel hose from tank to carbs to ensure there are no loose clamps etc (hard for any fuel pump to drag fuel when there is an easier path - sucking air alone). It's amazing the little things you might find while diagnosing things right from the begining. A kinked hose from being re-installed may sometimes allow some fuel through for idle and part throttle but not wot. When checking these things you may spot something related but not mentioned. I'm moving away from using hose clamps which can cut into the fuel hose to using cable ties/zip ties or whatever else they get called, they pull up tight enough, are cheap and easy to carry spares, and you can better feel how tight they are pressing into the hose. My local marine mechanic put me onto this method. You may find that the screws you adjusted are for the idle circuit only and may have no effect on any throttle position (part or wot).

Basics , basics need to be checked !!--What are the compression numbers ? Does spark in fact jump a gap of 7/16" on all 3 --Have you checked for a ruptured diaphragm in the fuel pump ?----------Have you run it with a timing light to verify good steady spark on all 3 cylinders ?--Have you checked for water in the fuel?

Well the last time I checked the compression it was at 42psi to 43 psi in all cylinders so I dont think that is the problem I guess I could check it again

Must be something wrong with your gauge , numbers like 42 PSI are not very good at all.---Should be between 100 and 120 PSI.

It's a good gauge it's ratio of 100 so 40 is 140