2006 Merc 50 hp 2 stroke idling rough/stalling

[Cooperdog]

I'm familiar with the basics of maintenance on small outboards (2hp - 15hp), but now have a Merc 50 2 stroke. It starts easily, and runs flawlessly above idle or very slow speeds. Never misses a beat when running high speeds. But it's started to stall a lot at just above idle speed. It's a very clean engine, and has been well maintained. Looking for some basic thoughts on where to start. I'm assuming I should start with checking or replacing plugs (I don't think they've been changed recently), and maybe run some seafoam through it? What about higher grade fuel? As far as I know, it's always had regular grade unleaded used, but would a higher grade possibly help? Thoughts.

 

[thomas15]

I have the exact same motor except mine is a 2005. And I'm having the same problem this year. I use mid grade gasoline so I don't think this will help. I had the carbs adjusted by a mechanic this also didn't fix the problem. I've done all of the obvious things, tightened every bolt and screw and still nothing. I take care of my motor and don't abuse it in any way.

The fuel lines and fuel pump have all been replaced in the last few years. But I'm thinking the next thing to look is a possible small leak in the fuel lines. A question I have is how can you check for a fuel leak or do you just start replacing hose? Either fuel lines or something wrong with the reeds. I'm stumped and hoping someone will answer with opinions because I want to enjoy the boat this summer. I hope someone can help.

 

[thomas15]

Question? Would it make sense to put a clear tubing at the fuel filter to see if there are air bubbles assuming a leak???

 

[DavidMoore]

Yes, for testing purposes only. To be replaced with fuel resistant lines after fault finding is completed.