Mercury Marine Primer Bulbs

You may need to fix or replace your Mercury Marine primer bulb if it is not creating proper suction. A small engine primer is a bulb of plastic with a hose running through it.

This hose feeds from the gas tank to the engine carburetor. All outboard motors have fuel pumps that are capable of lifting fuel from the fuel tank to the engine. If the Mercury Marine primer bulb does not work properly, it may need to be replaced. Most OEM rigging I have seen puts the fuel line Mercury Marine primer bulb within a foot or two of the outboard engine cowling. Most small engines will not start if the carburetor is dry. Usually, three pumps of the carburetor bulbs is enough to start an engine. Pressing the Mercury Marine primer bulb creates a vacuum that sucks gas from the fuel tank through the fuel lines and into the carburetor. Pressing the primer only a couple of times should supply enough fuel to mix with air in the carburetor and be ready for combustion. Quicksilver Mercury Marine primer bulbs have a new check valve and ball spring to ensure proper fuel flow. The (clear) fuel intake line runs from the top of the carburetor (straight nipple) and goes to the short post on the back of the Mercury Marine primer bulb. The Mercury Marine primer bulb creates the initial flow of fuel between the inboard, built-in fuel tank and the carburetor, in low-pressure, carbureted outboard motors. The Mercury Marine primer bulb on small engines is a small plastic piece that, when pressed down, draws fuel from the fuel reservoir and into the carburetor. The Mercury Marine primer bulb, which is located in the fuel line between the gas tank and the engine, is used to fill the carburetor with fuel when the engine is started cold. The rubber bulb resembles an oblong ball. Inside the bulb are two valves that open and close. The purpose of the Mercury Marine primer bulb is to prime the fuel lift pump with fuel. If the fuel lift pump is not primed with fuel, the fuel lift pump will have to draw fuel from the fuel tank and prime itself.

A Mercury Marine primer bulb is important because it helps to fill the carburetor with the correct amount of fuel. It does this by pulling fuel through the fuel line.