My dad has my grandpaws boat. It is an aluminum haul with a 2000 Johnson 50HP (J50PLSSM). It has given us problems always and I decided to try and work on it since my dad doesn't have time. Believe it or not, the boat has sat for at least 6 years and it started on the first crank once I primed it. I was kinda amazed, but the issue we always had is still occurring. It will run fine for 5 minutes... then turn off. No excessive smell of gas besides your normal gas/oil mix burning.
Back before it sat, we had it worked on by 3 different mechanics. None got it working long. I believe the last guy had it working good at his shop. We took it fishing and didn't make it an hour before it started acting up. That's the last time I remember using it.
So, I kinda looked around. Made sure the hoses were fine and they were. Spark plugs look clean. So I primed it again and turned it on. Took a few tries, but it ran. When it started to die off, I pressed the throttle and it ran fine for 30-45 seconds then wanted to die again. I kept pressing the throttle and the issue would be temporarily resolved. Obviously this isn't a viable solution.
Anyone have an idea? Wouldn't those mechanics have said it was the fuel pump when we brought it in if that was it? It's a pretty expensive part LOL. They could have made a pretty penny on it.