I have a RAM 500 that I have owned for the most part flown successfully for the last 7plus years. Lately I have many flame outs early in the TO roll but only one certain airplane. The engine runs flawlessly in my other airplane so I have concluded my problem is somewhere in the fuel delivery system and not the engine itself. I can sometimes make it quit just by shaking the airplane or bouncing it up and down or by rapid forward and backward movements. This happens with a full fuel tank and a full BVM uat which is orientated level (horizontal). I know that my orientation of the UAT is not optimum but it used to run fine like this so I tend to think that is not my problem.

One of my flying buddies thinks that perhaps my inline fuel filter is trapping an air bubble becasue I have the filter orientated horizonally which is also how it has always been and is infact that may in my two other planes with no issues. He suggests trying it orientated vertically instead and I will try most anything at this point if it might fix my problem. I dont recall ever hearing that the filter orientation mattered.

I am either going to try a new filter in the horizonal config or the existing filter in a vertical config and see if either one helps.

I guess I have three main questions:

1. What is the consensus opinion on filter orientation ?
2. If I orientate it vertically does it matter if the side going to the engine is at the top or the bottom ?
3. Anybody have any other ideas what my problem might be ?

Thanks,