94 Merc 2.5 V6 Not able to go full throttle

[Jloggi12]

I have not been able to go full throttle the last 2 times on the lake. It starts fine and runs fine. I can only go about 3/4 throttle(max 8mph per my garmin) before it starts to sounds like its bogging down. Last Summer I could go full throttle and was touching 13-15mph. I changed the plugs and the exterior water/oil filter and that did not help, any suggestions would be great. TIA

Pic of Motor for reference

 

[racerone]

What size boat is this motor installed on ?-----Post the results of a compression test.----Oil injection in service and tested ?

 

[Jloggi12]

What size boat is this motor installed on ?-----Post the results of a compression test.----Oil injection in service and tested ?

pic of boat is attached i believe its 20 footer.