3481 Solution to fuel system problem

11-11-2008, 06:09 AM

mike reibling | 3481 Solution to fuel system problem

As mentioned in my intro post I recently purchased my Seawind in July-08 from the estate of the late George Osborne. I had an engine failure soon after purchasing the Seawind. Fortunately, I was getting training at the time and Jack turned on the electric fuel pump which started the engine in about 10 seconds. The delay in restarting indicated air in the system which was a good clue as to the problem. Consequently I did not feel good about flying without the electric pump on, so after that I went to work on finding the problem. I started by installing clear fuel lines in various places. This confirmed air was getting in. The air was coming in the vent across the top of the header tank and it was flowing backwards through the recirc line from the electric pumps. I believe there was two problems associated with the air getting in. I now have them corrected by replacing the check valve and relocating it into a suitable place for the type of check valve used. First, the location of the valve. The check valve used was a valve that needed gravity to assist it in closing when it was subjected to air. So I corrected this by inverting the valve and letting gravity close it when air was trying to come in. Second, it had a bleed feature which only added to the problem. So I purchased a similar valve that had a no bleed feature. This seems to be working well now however I am considering changing it to a spring loaded check valve which would work in any position without gravity. Mike Reibling

11-11-2008, 06:11 AM

Mike | 3483 Solution to fuel system problem

Mike is this the origional fuel system (by the book) or has it been modified...? Could there be a problem with the engine driven fuel pump..? Or better yet the mallory pump bypass? Doesn't the mallory pump bypass internally bypass only one way? Since I have two pumps, as a general rule, I always fly with one pump on.

11-15-2008, 10:04 AM

mike reibling | 3486 Solution

I am not up to speed on the original system. My plane came with 2 electric pumps. I believe they are called "Airflow Performance". They require an external bypass line. In my case it is plumbed back to the top of the header tank. That is the line that has the check valve in it that was allowing the air to back up and cause the problem. I to fly with one electric pump on when ever I am low.