Also check your tank vent. I fixed a fellas pontoon boat after he had the motor worked on 3 different times and it kept losing rpm and was hard to start. His tank cap had cracked and he covered it with a plastic bag to keep water out. A friend asked me to take a ride on it to see if I could figure out what was wrong. Full throttle for about 10 mins and it fell on it’s face and didn’t want to start. I went back to see if it was anything obvious, primer bulb was sucked almost flat. Removed bag, opened cap to relieve vacuum and away we went. Best that motor had run all year. I recommended a new tank cap or take the bag off when using it.