I recently had an air problem in the fuel on Beta 20. I changed the primary fuel filter 3 weeks ago and engine ran fine afterwards until a few days ago when it cut out after 2 full days (12 hours) of running. On "cut out day" ran as normal for about 45 minutes, I turned it off and sailed for 20 minutes, and then restarted. Ran for 10 seconds and then stopped. I got a tow to dock where we added more fuel and bled the system. Took a long time for fuel to run from bleed screws. All fuel connections were tightened a wee bit and also the bowl at bottom of primary fuel filter. Engine restarted and ran fine for 12 hours over 2 days on return trip.
Could air have been trapped in filter when it was changed and worked itself free? What should I do next?
I am not sure here. You may have solved the issue by tightening all the connections.
I very much doubt that air was trapped anywhere as with the movement of the fuel within the fuel lines and the movement of the boat would have dislodged it so I suspect that you were sucking air in somewhere. Without seeing the installation myself, it is really impossible to say much more.
If the fuel hose is old and hardened up over time, this could cause air to come into the system.
It is also possible for the bleed screw at the top of the filter to be either slightly loose or for the "O" ring to be damaged.
These are just some ideas which I hope will be of help to you.