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I’ve
noticed the exhaust on one of my diesel inboards is dark gray, and sometimes
almost black in color. What does this mean? H.D., via e-mail
It could
be as simple as a damaged or dirty air cleaner, or you may have gotten
an improper grade of fuel. And while operating your engine in high ambient
air temperature may also cause this, a more serious internal reason may
be excessive exhaust back pressure brought about by anything from a past
modification to the exhaust system to some sort of blockage. It could
also be a faulty injector setting. Check the most accessible areas first
before calling in your diesel mechanic.
How
can I remove amine blush from a recent fiberglass job? B.W.,
via e-mail
Amine blush
is a byproduct of the epoxy curing process and appears as a wax-like film
on the surface of the area being worked on. It is usually caused by moisture
from condensation or when humid conditions react with the amines in the
uncured hardener material. If not properly removed it can cause adhesion
problems with subsequent coatings and interfere with the curing of some
paints and varnishes and all polyester gelcoats.
Do not
use detergents or solvents to remove it. Amine blush is water-soluble
and can be removed with an abrasive pad and water once the epoxy has fully
cured. Use a 3M Scotch-brite general-purpose hand pad to abrade and dull
the shiny surface. Then wipe the area with a clean, lint-free cloth and
check for any other shiny spots. Once all the blush has been removed,
you can continue with your project.
To help
minimize amine blush, make sure to follow all manufacturers’ directions.
Avoid working in humid conditions or where the ambient temperature is
below 65ºF, where epoxy will cure more slowly, thus allowing the
blush to form. In addition, check your resin-to-hardener ratio, as too
much hardener will not only increase blushing but also compromise the
epoxy’s strength. Finally, stir the epoxy mixture thoroughly to
evenly disperse the hardener.
I’ve
noticed that the spark plugs on my tender’s two-stroke outboard
become fouled quickly. What can be wrong? M.G., via e-mail
You may
be mixing the gasoline and oil at an improper ratio. Fifty parts gasoline
to one part oil is the norm, but check your engine manufacturer’s
recommendations to be sure. Other possible causes are improper spark plugs
and excessive idling.
Need
help with a maintenance problem? Write to Maintenance Q & A, Power
& Motoryacht, 260 Madison Ave., 8th Fl., New York, NY 10016. Fax:
(917) 256-2282. e-mail: kkreisler@primediasi.com.
No phone calls, please.
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