Air in the diesel

If you pour diesel into the tank to enthusiastically, you can end up with air bubbles becoming trapped in it, which can bring your engine to a halt.

Swallow’s BMC 1.5 engine is fitted with two filters – one just as the diesel leaves the tank, and the other where it flows through the engine. Eric asked us to try removing air from both of these filters.


Filer 1


Filter 2

1. Firstly, try the first filter (the one nearest to the tank).

Turn the diesel tap OFF.

Hold a container beneath the filter. Unscrew the centre nut on the top and watch for air and diesel blubbing out.

Replace the nut tightly.

2. If this hasn’t sorted the problem, try the second filter (the one fixed to the engine).

Turn the diesel tap ON.

Loosen the nut in the top centre of the filter – say about three turns (you only want it slightly open.)

Low on the the side of the engine, somewhere beneath the fresh water cap, is a dome-shaped thing. Feel beneath this and there is a small trigger which you can jiggle up and down. Slowly pump this, and watch for diesel and bubbles coming out of the nut on top of the filter. Keep going until the bubbles stop and you’re only getting diesel.

Retighten the nut and give everything a wipe.

Hopefully, the problem is now sorted!