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[Amel Yacht Owners] Exhaust stain


Joel F. Potter <jfpottercys@...>
 

Hi Bill,

I hope you and Sara are both well and happy.

Minimizing the soot on your portside requires a two prong attack.

First, since your Volvo engine is more prone to produce soot than the later
YANMAR engines, the mechanical health of the engine is very important. When
at idle in a marina, look at the exhaust outlets, if you see evidence of a
sheen on the water (like when you spill gas or diesel onto the water) your
injectors probably need servicing. There is a lot of controversy regarding
servicing versus replacing the injectors. You will generally have better
luck replacing them.

Your turbocharged engine needs special treatment. 1 hour out of each 10 (or
15 minutes out of each 2 1/2 hours, which is actually better) the engine
must be run HARD at 2600 RPM or more. THIS WILL NOT HURT THE ENGINE. To
make a long story short, this helps preclude "COKING" the turbocharger or
coating the inside with carbon. If the engine smokes a lot at high power,
the injectors or injector fuel distribution pump needs servicing. Worse
case is extreme mechanical wear which is a prelude to an overhaul but this
is unlikely at under 5000 hours unless the engine has had abuse, poor
maintenance, or has been severely overheated.

Even the most perfect diesel motor will make some soot, which is today now
called particulate matter and the cause of considerable scientific debate
regarding health issues and even global warming. I digress.

To minimize the effect of these particles, wash then polish the hull at and
after the exhaust port. It's hard work, as you know, but get it perfectly
clean. Next, polish the gel coat again with a proprietary gel coat polish
with a small amount of polish/grit in it. This smoothes the pores of the
gel coat. Finally apply several THIN COATS of a marine carnuba wax with
silicone or, better yet, TEFLON. Eight thin coats, such as when wiping the
wax on with a water damp sponge containing some wax are much much better
than one or two or three thick coats as you polish/wipe off all but a thin
layer with each application. In the Caribbean, you need to re-wax every
other month. It's a pain in the keester but not as bad as removing the
black soot stripe.

I hope this helps.

All the best,
Joel