New Mercury knocks

[jevery]

I have a new 06 Mercury 115 4-stroke. When on the water with the cowl in place it runs and sounds normal, though not a quiet as I expected for a 4 stroke. Running on muffs with the cowl removed I can hear a knocking. Not real loud, but clearly audible. It seems to be coming from a part attached to the valve cover. It is a silver disk about the size of a can of Skoal with two hoses attached. They appear to be fuel hoses so I’m guessing fuel pump? Probably cam driven? Could it be similar to the old style Detroit diaphragm fuel pumps that are powered from a lever riding on an eccentric cam? That would explain the noise, but it seems like outdated engineering with the electric pumps widely used today. Does anyone know if the disk is indeed a fuel pump and if the knocking is “normal” for this engine?

 

[05GlastronSX]

Re: New Mercury knocks

knocking isn't normal for any engine. Plus, it's brand new and under warrenty, take it in to the dealer and let them deal with it. You could(most likely) void your warrenty if you try to mess with it yourself..

 

[marinegrh]

Re: New Mercury knocks

definately take it in and dont let them tell you its normal, you are correct about the skoal can being a fuel pump, but it should not be loud enough to make you worry about it everytime you run yor engine on the muffs, the pump is driven off the cam and that syyle of pump has been in use for a little while but definatley take it to your dealer, and if you dont trust them, find another one or get a merc rep involved...fair winds and repost with your results