Mercury Outboard Boat Motor Powerheads

A Mercury outboard motor is made up of a lower and an upper unit. The lower unit sits in the water and houses the propeller and water pump, while the upper unit houses the engine that turns the propeller. An essential part of the upper unit in the outboard motor is a part called the powerhead.

What is a Mercury powerhead?

An outboard motor powerhead serves as the base upon which all the other marine motor parts are attached. The powerhead is a complete engine that houses the rods, bearings, crank, piston, rings, and other essential engine parts. A comparable part in your car or truck is the engine block.

What information do you need to buy a new powerhead?

You can get either a brand-new powerhead or a rebuilt one. To ensure you obtain a powerhead that fits into the upper unit of your motor, you’ll need to get the serial number of the old one. The serial number is used to match comparable powerheads. The serial number is located on an unpainted silver-colored plug attached to the engine. You may have to search a little bit for the plug since it can be in different spots depending on the size and horsepower of the engine.

If you have difficulty finding the plug, another option is to call a Mercury outboard motor dealership or service center and give them the year and horsepower of the motor so they can look up the serial and parts numbers for you.

How do you replace a powerhead?

The first thing you have to do is remove all the parts connected to the powerhead. This involves removing the flywheel, ignition coil, and all the electrical and fuel connections. You’ll also need to disconnect the unit from the flange on the gear case. There are 4 bolts that will have to be removed. One bolt is in the front, one is at the back, and one is on each side of the unit. Once the parts and bolts have been removed, you can lift the unit up and take it off of the motor.

What tools do you need?

You need to make sure you have the right tools to do the job of replacing the powerhead. You’ll need an adjustable wrench, a ratchet with a set of metric sockets, and a flywheel remover. You should also use a camera or smartphone to take pictures of everything before you take it apart. The pictures will help you determine what part goes where when you put everything back together.