Clean petrol is vitally important for a smooth running engine (just like oil, coolant etc) and the condition of the tank the fuel is stored in can have a major effect on how the engine starts and runs.
Petrol tank filler hole looking fairly clean from the outside
We checked the interior of a fuel tank from a Honda NT650V Deauville as, although it looked clean from the outside and the filler hole looked clean, it sounded like debris was moving around inside the tank.
We used an endoscopy camera that plugs into a mobile phone to check the inside (these cameras are fairly cheap and are handy as hell!).
Although the camera doesn’t take particularly good pics or vids, it was ideal for examining the internals of the tank.
Internals of the fuel tank showing alot of rust and debris
There are many problems that can be caused by rust and debris in the fuel system, some of the problems likely to be encountered are:
- Rough Engine Running: Particles and debris can disrupt the flow of fuel, leading to sputtering, misfires, hesitation and loss of power (especially during acceleration).
- Difficulty Starting or not starting: Debris clogging the fuel system can make the engine hard to start.
- Stalling: An inconsistent or restricted fuel supply can cause the engine to stall unexpectedly.
- Decreased MPG: When the engine is not getting the proper fuel mixture due to clogs, it runs inefficiently and uses more fuel.
More rust and corrosion inside the tank.
None of the rust and corrosion in the above pics could be seen from the outside through the filler hole.
Note – You can often hear debris and rust inside the petrol tank if it’s drained of fuel and given a shake.
Rust patches inside the tank, the rust had started to flake off into the fuel.
Parts of the fuel system that can be damaged or not run properly due to debris and rust include:
- Filters: Dirt, rust flakes and sludge can clog your fuel filters and pipes. Filters are designed to catch some dirt and debris but can get overwhelmed by large amounts of debris which can block the fuel flow.
Also, as in the pics above, fuel filters inside the tank can become dislodged which renders them totally incapable of stopping any dirt. - Carburetors: In bikes with carbs fine particles and debris can clog the jets and passages in the carburetor (these are very small and difficult to clean).
- Fuel Injectors: In fuel-injected bikes contaminants can damage the fuel pump and clog the tiny openings of the fuel injectors, (which can lead to expensive repairs!).
- Fuel Pumps: The fuel pump has to work much harder to pull fuel through clogged filters and debris which can lead to to premature failure or blockages.
The pictures above show a hole starting inside the tank and internal coating starting the flake off (which also contributes to the debris)
Rust can begin to form when water gets into the tank through condensation (especially if the tank is left half-empty) and from ethanol containing fuels (like E10 petrol) which attracts moisture. This water reacts with the steel, forming rust.
Rust flakes off and acts as a contaminant, moving through the fuel system. Critically, rust can eventually corrode through the tank itself causing pinholes and leaks.
Note – We have found that E10 fuel left in the tank can cause rust problems in the tank and fuel system (detailed blog post about this here..).
Disclaimers:
The information provided on this page is ‘to the best of our knowledge’ and should not be taken as 100% accurate!!
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