PassageMaker - July 2018

July/August 2018 passagemaker.com 25

Proudly built in America • Burlington, WA

http://www.AspenCats.com • 360-668-4347

Dare to Adventure

Advanced Design, Precise Construction

POWER CATAMARANS

ride against the cover plate, the better the
pump output. The inside of the cover plate
should look polished and slightly worn,
but replace it if you can feel grooves or pit-
ting. In a pinch you can clean and polish
the outside of the cover plate and reverse
it. But this is only a temporary solution as
the stamped lettering will create impeller
wear. Inside the pump housing at the back
you will find a wear plate and the same
standards apply here as well.
The cam also can wear. If it has
turned pink from corrosion, has pitting,
or exhibits wear grooves, it should be re-
placed as soon as possible. Some would
even suggest that any time you replace
the impeller you should also replace the
cam and the wear plate.

WARNING SIGNS
As mentioned earlier, your seawater pump
contains at least one seal (for seawater) and

possibly a second seal (for the oil on gear-

driven pumps). The pump housing includes

one or two “weep holes” so that any fluid

that leaks past a failing seal will be visible

here. Occasionally debris in the seawater will

create a minor, temporary leak in the me-

chanical seal. If you have a minor seawater

leak that disappears after a day or two, there

is no need to do anything. Any oil leak, how-

ever, or any ongoing seawater leak points to

a failing seal. In those cases, rebuilding or re-

placing the pump should move onto your list

of upcoming maintenance.

Losing small amounts of seawater

through a failing seal does not present an

imminent problem—after all, there is plenty

more seawater where that came from. But

I inspect many boats with downstream

damage that has gradually occurred from

minor but continual leaking. These issues

include flaking engine paint, rusted engine

mounts, and damaged engine wiring con-

nections, so it makes sense to tackle these

leaks promptly.

PUMPED UP

Unlike so many of the new digital

products, the engine seawater pump

remains accessible to boat owners.

With a minimal number of spare parts

and some basic skills and tools you

have a high probability of successfully

dealing with a seawater pump problem

on your own. Your first attempt, how-

ever, should always be at the dock, not

at sea. Some configurations require re-

moval of other components or special

tools (and in some cases replacing the

whole pump will be easier than chang-

ing the impeller). By monitoring engine

temperatures and keeping an eye out

for oil or seawater leaks at the pump,

you will be able to stay ahead of any

brewing trouble. Q