Fuel Pumps & Sending Units
About Fuel Pumps & Sending Units
The fuel pump moves gasoline from the tank to the engine, and the sending unit is the float and sensor in the tank that tells the fuel gauge how much is left. Riders look here when a machine cranks but will not start, cuts out or stumbles under load, or when the fuel gauge reads wrong.
There are a few kinds of pump. Electric pumps and complete pump kits sit in the tank of most fuel-injected machines, and some kits include the seal and strainer. Vacuum-operated pumps, which are common on carbureted machines, work from the engine's own pressure pulses and are listed here too. Rebuild kits replace the worn internal parts of a pump you already own, which suits a pump that is otherwise sound. A cracked housing or a dead motor calls for a whole new pump. Titles often list a range of years and models, so pick your machine in the Ride Finder at the top of the page, and see our guide on why a part did not fit.
Brands here include UFO, Bolt, Helix, Quantum and Mikuni. A new pump works best with clean fuel, so replace Fuel Filters at the same time and check Fuel Hoses, Lines & Pipes for cracks. Injected engines also depend on Fuel Injectors.
FAQs on fuel pumps and sending units
How can I tell if a fuel pump is failing?
A failing fuel pump can cause hard starting, stalling, a stumble under load or a whining noise from the tank. Weak fuel delivery also comes from a blocked filter, a bad relay or a blown fuse, so check those first. A fuel pressure test is the sure way to confirm the pump.
Should I buy a rebuild kit or a whole fuel pump?
A rebuild kit replaces worn parts such as seals or diaphragms inside a pump that is otherwise in good shape. If the electric motor has failed, the housing is cracked or the pump is badly worn, replace the whole pump or pump kit instead.
What does a fuel sending unit do?
A fuel sending unit is the float arm and sensor inside the tank that reports fuel level to the gauge. If the gauge reads empty or full when it should not, but the engine runs normally, the sending unit is a likely cause, rather than the pump.
Should I change the fuel filter when I replace the pump?
Yes, that is good practice. Dirt and rust flakes from an old tank or filter can damage a new pump. Fuel is flammable, so follow the manual's steps for relieving pressure and disconnecting lines, and work outdoors away from sparks.
