74 Johnson 70hp lost rpm/top speed

[Kirschking]

70hp on a 16ft Jon boat use to run around 33mph according to GPS now only reaching 24mph and doesn't sound like it's reaching as high of rpm as it use to...no tach. I'll add ran great besides idle was always little low and sometimes died when going into gear. Died one day took carbs apart and found junk in them
-Decarbed engine with sea foam method
-Took apart and cleaned carbs spray can cleaner compressed air
All new fuel lines including tank
-New spark plugs
Jumps 7/16 gap on all 3, bottom might be ever so slightly not as bright of spark
-Compression around 120 on all 3
-Timer bass moves freely and reaches stop
-Only adjustment I changed after carbs reinstall was idle set screw backed off to get a little more idle rpm
-All carbs open the same time and butterflys are horizontal
Starts and idles perfect now, takes off seems might be tad slower to plane and runs good at wot just doesn't sound like the rpms there and definitely slower
Any ideas where to look next

 

[F_R]

Look for evidence of water intrusion into cylinders, especially the center one.

EDIT: So you say there was junk in the carburetors. Are you positive you got it all out, including the high speed jets? Any chance it just pumped in more junk?

 

[Kirschking]

How would I go about checking for water intrusion?
I'm pretty sure I got everything out I cleaned each one twice but there's always a chance something else got in there or missed something. Will be cleaning carbs again tonight and put new in line fuel filter tomorrow.
Would water cause like s miss fire and change the look of the spark plug?