Priming Bulb - Small hollow plastic bulb used to 'prime' the fuel line when it's first connected to the outboard.Normally incorporating plunger clip to secure it. Fuel Hose - Non-perishable plastic line connecting the tank to the outboard fuel line port.Air-vent Screw - A small screw or valve, usually plastic that should be loosed to allow to enter the tank when the outboard is running but closed (to restrict fuel fumes) when not in use.These are typically 10 or 15 litre tanks that connect to an Fuel line port on the front of the outboard with a locking clip. Larger outboards that consume more fuel will have an external tank giving longevity and range to your days on the water. a small plastic container sitting alongside or above the engine and hidden under the cover. Small outboards (2-5HP) will have an internal fuel tank, i.e. Sometimes incorporating a fine mesh filter to stop the ingest of dirt and plant material. Water Intake Hole - Small hole in the gear case for fresh (or salt!) water to enter the cooling jacket.Like most oils gear oil should be changed according to the manufacturers guidelines - usually number of engine hours or period of time. Gear Oil Drain Plug - The exit point for the gear oil for when it needs changing.Typically the gear oil should be flush or 'level' with this opening. The level of oil is checked and topped up by opening the gear oil level plug.

This gearing is enclosed in the gear case (the bulb shape just behind the propellor) which is lubricated with a special type of high-temperature gear oil. Gear Oil Level Plug - All outboards have a gearing at the bottom of the drive shaft to transfer the energy through 90 degress into the shaft the propeller is attached to.Trim Tab - not really a component as there's not serviceable element to it but simply a moulding on the back of the anti-cavitation plate designed to aid steering performance.This cavitation reduces the efficiency and performance of the outboard hence manufacturers incorporate a metal plate above the propeller to reduce the impact of cavitation. Anti-Cavitation Plate - Cavitation is a hydro-dynamic phenomenon where the propeller thrust reduces water pressure around it allowing air to get pulled into the space.Anodes come in different metals and strengths depending on need. It is a called a 'sacrificial' anode as it slowly wears down over time. Anode(s) - Take many formms and are often absent on smaller and older outboards essentially an anode is a piece of metal designed to be the softed or 'least path of resistence' for electrical current leeching out of the outboard.This bracket usually incorporates a small pin that can be moved into one of half a dozen holes in order to finely tune the engine angle into the water. Clamp Bracket - A large u-shaped bracket usually with 2 sides that is used to attach the outboard to the stern or transom of your rib or hull.Just like your car this oil needs to be changed periodically and as such necessitates an Engine Oil Drain Plug.

4-stroke outboards that are lubricated through a fuel/oil mix like 2-stroke (more - differences between 2-stroke and 2-stroke) engines require oil to maintain engine lubrication.

Engine Oil Drain Plug - Pretty self-explanatory really.

Flush Plug - On larger outboards there will be a special opening for 'flushing' the water cooling circuit.

The exit point for this cooling circuit is call the Pilot Water Hole. But outboards are an 'open' cooling system so unlike your car instead of the same water being pumped round in a sealed circuit outboards just pump the heated water and dump it back in the water.

Pilot Water Hole - Most outboard engines are cooled by permanently pumping water around the main engine block and head.

Power Trim or Tilt Switch - Mechanical lever to adjust the rake angle of the outboard in the water depending on the tender or boat hull design in order to maximise the efficiency of the engine thrust being placed into the water by the propeller.

And yourself from the engine and all that heat and electrics.

Motor Cover or 'Cowling' - U/V resistent plastic cover desgined to protect the main engine compartment from the elements.

Power Trim switch) but for most outboards will have the following: Not all outboards will have all of these componets (e.g. New to Outboard Engines? Here's our beginners guide to the main components and what they do. Guide to Outboard Parts Beginners Guide to the main components of an Outboard Engine

Mercury outboard parts diagrams