I have a 2016 merc 150 fourstroke on a 195 txw. I lost speed before and got prop work done and gained my speed back. But I have lost it again, I should be doing 60 and i am only doing 50. I just put a new prop, same exact prop as before, because i thought maybe my prop was shot, but it didn't help much. I'm running 5400 rpm and have no problem with the hole shot. My boat did start taking on water after very rough conditions on Toledo bend and my top speed has not been where it should be since that trip. Also, it could just be my imagination but my motor sounds more high pitched than it did before. any help?