162 seamanship secrets
Air System Checklist
Check air fi lters and clamps (before start-up). Smaller engines oft en have the air
fi lter housed inside a metal cover on the side of the block, and some small engines do
not have an air fi lter. Some large power vessels carry external fi lters clamped to the
air intake. Check the fi lter for excess dirt and grime. Clamped fi lters tend to loosen
from engine vibration, so check the hose clamps oft en and tighten as needed.
Air System Maintenance
Clean or replace the air filter element. Annually, or more often if needed,
remove the air filter and clean it as described in the instructions below:
Paper element fi lters. Tap the fi lter on its side to remove deposits. Continue
to turn and tap the fi lter around its circumference. Replace as needed.
Foam element fi lters. Use a mild solution of detergent and water. Dry
thoroughly before reinstalling.
Metal element fi lters. Wash the fi lter in solvent.
THE CHARGING SYSTEM
Charging System Checklist
Check covers and straps (before start-up, while underway). Each battery needs
its own cover to protect the terminals from dropped tools, which could cause
sparks and even an explosion. All batteries must have strong webbing tie-down
straps that wrap around the batteries (over the covers) and are through-bolted
to the battery shelf or box. Tie-downs must keep the batteries in place—even in
a knockdown or broach. Replace defective or worn tie-down straps.
Check that the alternator is charging normally (aft er start-up). If you
have an ammeter, it should show charging. If you don’t have an ammeter, look
at the charge warning light, also called the ignition light. Th is will extinguish
as soon as the alternator comes on line. If it stays lighted, you have a problem.
It may mean that the alternator belt has failed, and since this belt also drives
the water pump, the engine will soon overheat.
Charging System Maintenance
In his book Troubleshooting Marine Diesels, Peter Compton recommends three
steps for the maintenance of the lead-acid batteries found on most boats:
- Battery size and type. Use batteries that are the correct size for the job at hand.
If you have two batteries onboard, reserve one for no other duty than starting
the engine. Starting batteries have to deliver a burst of power to start your
engine. Th ese batteries will show a rating of cold cranking amps. Compton
recommends 2 to 3 cranking amps for each cubic inch of engine cylinder
volume. Look in your engine manual for the cubic inch measurement.