I see you’ve been having this issue since 4-19? Those motors are some of the BEST Mercury ever produced. Maintenance is the big key! They'll last a long time & give trouble free service for a lot of hours IF you’ll do it. Contact me on PM if you want. I can give you some tips on it. They’re one of my longtime favorite motors. They’re little sweethearts if ya treat em right

Or you can clean the injectors yourself. Get a can of sea foam, a 12 volt battery, a momentary button, some 18g wire and an air compressor. Oh. And a piece of 3/8id hose. There are lots of videos on how to do it. It does a decent job.

You will likely need to change filters too.

My Yamaha 4 stroke needs this done around once a year or 100 hours. Whichever comes first. I know it’s time when I lose a couple mph and planing takes some effort. I have a spare set of injectors I bought from Amazon for cheap. I clean them at my leasure and swapping them on a Yamaha takes about 5 minutes start to finish.

Also...it could be spark plugs. Do NOT cheap out on plugs. Get NGK plugs. Not the super iridium or platinum junk. Just the exact OEM quality plug the motor calls for.

I guarantee you cleaning injectors, new plugs, and maybe new filters will have that boat jumping on plane.

Dirty injectors will slightly lower top end speed, but they will demolish your ability to get on plane. Your boat needs that torque to get that hull up and out of the water.

Also, this hot humid weather will have a noticeable impact on a outboards power. Some motor/boat combos are so bad that some owners change props between warmer and cooler weather.

Really, mine are 18yrs old and haven't been touched

Injectors should be cleaned and flow tested after cleaning to ensure satisfactory operation. Several injector cleaning services will tell you what order to install them in based on flow after cleaning and testing.

I have it going to the shop next month, I will let y’all know what the issue was when I get it out!