1999 50hp 4 stroke merc low power

[blakevw]

I have:
changed the plugs
changed the fuel filter
topped up the engine oil level
run a can of seafoam
put on the spare prop

nothing seems to have worked. the boat will not get up on step without me going to the bow. Problem started out of the blue 4 days ago while out on the water. suggestions?

there is a video linked that shows the low power issue. (https://www.youtube.com/watch?v=Arnav_fKc5I)

Thanks in advance!

 

[blakevw]

anyone? this is a real stumper...