Fuel manifold on newer 912 ULS engines

[Dave S]

Bruce,

There is quite a bit of historic information on this list regarding issues with the "old system" without a return line.

Do an Advanced search using the terms "Vapor Lock"

As Jim O said, this is not a 100% deal; however, the current design Rotax system with the return line solves many of the flooding, hot soak and vapor lock issues that are somewhat uncool to experience with the old system.

Certainly a person with an experimental can make deviations from plan; however, it's hard to beat doing the installation completely to specification for best reliability.

How well the return system works depends on how closely the installation matches the design. The check valve is critical to prevent unfiltered backflow to the carburetors, where the return line goes back to relates to the potential for recycling volatilized fuel back to the engine; and, the orifice regulates the correct amount of return flow.

[Cowboy]

Bruce,

There is quite a bit of historic information on this list regarding issues with the "old system" without a return line.

Do an Advanced search using the terms "Vapor Lock"

As Jim O said, this is not a 100% deal; however, the current design Rotax system with the return line solves many of the flooding, hot soak and vapor lock issues that are somewhat uncool to experience with the old system.

Certainly a person with an experimental can make deviations from plan; however, it's hard to beat doing the installation completely to specification for best reliability.

How well the return system works depends on how closely the installation matches the design. The check valve is critical to prevent unfiltered backflow to the carburetors, where the return line goes back to relates to the potential for recycling volatilized fuel back to the engine; and, the orifice regulates the correct amount of return flow.

Thanks Dave and thanks to everyone who replied. I talked to one of the techs at Lockwood today. He said yes you need to run the line. He did say it was alright to tee it into the header tank. I put a 3 way tee in the line between the fuel tank and the header tank. So, I think I am good to go now.. Appreciate the feeb back

Bruce