A question we are often asked is "which is better… OEM or Aftermarket parts?"

When you take your boat to the dealership's service department for repairs you're probably getting Original Equipment Manufacturer (OEM) engine parts. However, if you take your boat to an independent shop, you'll most likely get aftermarket parts. Is there anything wrong with that? Does a less expensive part mean ...

Reversible Tilt Trim Motors

Today’s tilt-trim motors use wire wound or permanent magnet fields. Before you can accurately test the motor you must know what type it is.

Wire wound field motors will normally have three wires and will usually have four screws placed around the
perimeter of the motor case. If the motor has only two wires; it is usually a permanent magnet field motor.
However, some older Mercury Marine wire wound field ...

Water intrusion is the #1 cause of starter failure. If water gets pumped into the motor portion of the starter from the flywheel, it will not drain out. Rust and corrosion will destroy the inside components of the starter.

The #2 cause of starter failure ...

POINTS TO REMEMBER
The battery is the heart of the electrical system. Always start troubleshooting at the battery. Never store a battery in a discharged state. Never add anything except distilled water to a battery.

IMPORTANT BATTERY FACTS
A good battery can provide four or five years of worry-free service with the right kind of care. Bigger is better! The battery you are replacing does not have to be the same size as the original. It is always better to have extra battery capacity. ...

ENGINE HORSEPOWER REQUIRED FOR ALTERNATORS
For every 23 AMPS of alternator output about one horsepower is required.
FOR EXAMPLE: A 12 volt,115 AMP alternator requires 5 horsepower.
(115 divided by 23 = 5 horsepower). A 24 volt unit requires twice the horsepower.

ALTERNATORS ARE NOT BATTERY CHARGERS
Alternators are designed to supply current for the accessory load and maintain the charge of the ...

Safety Modifications

Electrical systems^[3]

• Marine starter motor — it has an internal screen to minimize the egression of spark movements.
• Marine alternator differs from an automobile alternator — it has an internal screen to minimize the egression

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