theoldwizard1

Okay,I am the classic weekend boater. I got the boat out for the first time this year and the engine is not running right. Last fall, I drained all of the fuel and replaced it with fresh premium fuel treated with StaBil. I fogged the engine and buttoned it up. It started right up this spring on the muffs (EFI is great). I get out on the lake yesterday and throttle up and the engine starts missing. Sometime it clears up, but above 4000 RPM it is almost continuous. I checked the fuel filter/water separator. No water and filter looks clean. The bulb will stay hard over night. In the AM 6-8 bulb pumps and the bulb is still not fully hard. Of course all the marina in the area say they can get to it next week, so I am on my own for this week. My guess is air leak on the vacuum side of the mechanical pump or mechanical pump diaphragm leak. Other guesses ?

Anything new from the outboard manufacturers ? Can you catch a ride on the new Yamaha 4 stroke V6 ?

I have a Merc-Yamaha 115 that is coming up on 10 years old, but still has well less than 200 hours on it. About 4 or 5 years ago, I was in Charleston SC and took a harbor tour. The boat had twin Yamaha 150s. After the tour, I asked the skipper/owner what he thought of the engines. He said he loved them. He also mentioned that he had sold his old engines, twin Yamaha 115s, to some one else the year before with well over 500 hours on them and they were still running strong.