Merc Tracker 25 loss of speed after warmed up

[bang4dabuck]

This is my bros motor. When we first set out we get 20 MPH in the morning. We were back trolling after but when we would try to move to a new spot or calling it a day we could only get about 10 mph. Motor sounded and acted the same. No rough idling or smoking. This pretty much happened all week, first thing heading out 20 then mostly back trolling and by the end of the day full out maybe 10. Spun hub maybe but why so consistent can't be

 

[iggyw1]

This is my bros motor. When we first set out we get 20 MPH in the morning. We were back trolling after but when we would try to move to a new spot or calling it a day we could only get about 10 mph. Motor sounded and acted the same. No rough idling or smoking. This pretty much happened all week, first thing heading out 20 then mostly back trolling and by the end of the day full out maybe 10. Spun hub maybe but why so consistent can't be

If it were a spun hub on the prop, it would sound as though you put her in neutral. Only thing I may suggest , and it happened to me, do you have a floor in the boat that is up above the hull? If so check for water below the floor. My floor is about 6" above the hull. When this happened to me (10 MPH top speed) it was because of a lot of water under the floor.

 

[quicktach]

Trolling in lots of weeds ?

 

[bang4dabuck]

WATER maybe WEEDS no. I'll run that by him since ran the bilge. We do get a bit of water over the stern while back trolling.