I have a 2015 mercury 40 hp efi tiller outboard. It’s ran fine up until the last few months. I fire it up and it will run at wot for around 10 minutes then start to bog down and lose power. I can then restart it and it will run fine for a little longer than persist with the same problem. I’ve replaced the fuel lines, a whole new tank, spark plugs, cleaned out the vst it was full of nasty fuel sedamint at the bottom but still ran bad after cleaning.

 

You need to go to a MERCURY OUTBOARD MOTOR site.

Mercury (Ford Motor Company) doesn't make cars any more.


'95 MERC at Flaming Gorge, Utah.
Ford did/does not make outboard motors.
Good Luck !!