robertjh2239
New member
Have a 2012 Merc 150hp 4 stroke with 334hrs that all of the sudden wont go above 2500rpm. Boat has been with mechanic for going on 5 weeks. They replaced the neutral safety switch (which they said was the issue) and another switch (not sure what it was). Also replaced fuel filter (again) and feul/water seperator filter as well as plugs (twice). They tested fuel pump and report is working properly. According to the comptuer the engine is in guardian mode but it wont tell them why. I feel they are stumped and looking for any recommendations of what it might be.