914 Problem Has Returned and The Previous Solution is Not Working

Hi Craig

The type 914 has a return line directly off the fuel regulator on the airbox.  When you turn on the fuel pumps it will circulate fuel back to tank (or where ever you have it set for) This should clear any vapor build up in the lines downstream of the pumps as the volume is very high.  The circulation cools the fuel.  Check to see if your return line is far enough away from the pickup port in the fuel so that it does not grab the bubbles of returning hot fuel.  If this is the case the vapor lock will be difficult to clear.  This also happens when people plumb the return line just to the top of the small gascolator on the firewall.  The very small volume will simply circulate the hot fuel back to the engine.  

Don't know if that is the issue but i would check this first should you suspect vapor lock.  Suggestions on the fuel system are found in the 914 installation manual at https://www.flyrotax.com/p/service/technical-documentation.com .

Cheers

It definitely was vapor lock and it was resolved by starting it with the pumps off.  Worked like a charm.