My step-son has a 115 hp Suzuki 4 stroke on his pontoon boat that has run fine for 1 1/2 years now. When we took it out the first time this summer it would get up to 6000 rpm and then all of a sudden it would drop down to 5000 rpm for a second or two then pick back up to 6000 rpm. It did this several time so I told him I thought he had gotten some water in his gas but he said the marina has winterized it last fall so the fuel stabilizer should have removed any water. I suggested we add some stabilizer to see if it would help so he did but we did not get to run it after that. This past week he called the marina and told them he was having a problem with it. I took the boat out today and it ran fine so I called him to let him know that all was fine with it and that is when he said the marina had called and told him there was something wrong with his prop that was giving him the trouble. My question is how can a bad prop make a boat loose 1000 rpm then pick back up and loose it again over and over? I think they did not winterize the motor but charged him for it and came up with this prop thing just to cover their butt.