Re: 2005 Johnson 115 bogs down after 15 minutes
Sounds suspiciously like the tank isn't venting properly.
When the engine starts bogging, start pumping the primer bulb. if it collapses (won't open back up after you squeeze it), it means an obstruction in the tank, or the vent is stopped up or closed.
If on the other hand, RPM's pick back up, that would indicate a weak fuel pump
