Mr Wizzard wrote:
So I finally got about 20 hours (I think) on my new 2005
Bayliner 175 Capri, and within the forst 10 hours, I
noticed a noise in the engine, and it seems pretty
pronounced at idle. It like a rattling noise, but the
best way to describe is that it sounds just like that
rattling sound of a diesel engine. I stuck my head
clean down in the engine compartment, and it seems
like its coming from the cover on the left side below
the head (where I think the lifters are at). This is a
Merc 3.0L straight 4. I'd "like" to think that it is
valve lash, but that "rattling", diesel-like sound has
got me worried, because in my car engine days,
this sounds just like piston slap/wrist pin type noise.
And when I really wedge my head down in the
engine compartment, it "almost" sounds like its
loudest from the back of the engine near the
flywheel/coupler, but I can't say that for sure.

Is this normal? - can someone shed some light
on the nature of this sound, and why it sounds
so much like piston/wrist pin type noise, and
not like the lifter noise of the old V-8's of years
gone by? Could it be just the physical layout
of the Merc 3.0L straight 4 and its valve train
layout? And if it is valve lash, is it normal to
need adjustment after 20-ish hours on a new
motor?. And one last question, does anyone
know for sure if the 2005 Merc 3.0L has
solid lifters, or hydralic lifters ? Is this
something that Olympic Boat centers is used
to doing in the fist few hours of new Merc 3.0L's ?

Thanks in advance!

It might not hurt to have somebody actually listen to the engine and
render an opinion after hearing the noise. It may be a "break-in" issue
that is supposed to be dealt with at X hours. Anything in the owner's
manual that indicates a service adjustment at this short interval?

Olympic can probably answer your question authoritatively and
accurately, but if you want a second opinion try calling Pat of Pat's
Marine Engines over at Nickerson Marina.