I have a 95 90 horse Mariner with a new powerhead with approximately 125 hours on it. Lately, it has been losing prime and the engine will die. I have to pump the bulb many times before the engine will start again. Yesterday I noticed that when I added throttle to come on plane the engine seemed to be missing at lower throttle position, once the rpm's were up it ran fine. When trying to run it up on the trailer yesterday, the engine would die but would restart, then when throttle added would die again. Your thoughts.