Hi Roger,
"230F - 245F oil temp on take off is very normal here in the west US this time of year and that by itself shouldn't cause vapor lock. All of us have those oil temps on take off including many RV12's and none have vapor lock on take off or at 230F.
Out here 230F is a low take off climb temp this time of year. Usually the fuel hoses need to heat soak to cause the fuel to vaporize."
My experience is ;
Vapour lock or fuel vaporisation (same thing) has always been a ground based phenomena.
What seems to happen is;
Hot ambient temperature - I nominate 30C & above (just a gut feeling)
Engine run to full or near stable, operating temperature - this is usually flight time but could equally be long taxi/ground run.
Engine shut down.
Followed by a short period of inactivity - how long? probably 10-30 minutes. This is when your "heat soak" of the fuel lines over the engine occurs. The time for this to occur will vary according to ambient temperature, engine installation, degree of fuel line insulation, mitigating management eg cowling into wind, opening of inspection hatches, installation of top vents, etc.
Fuel boost pump on - rapid pumping sound continues/may not get up to full pressure.
Engine start - may start normally - could be quickly followed by engine stop or rough running - hard to restart (choke may help).
Engine eventually runs normally.
Engine develops full take-off power.
Sudden reduction in power on ground role/climb out (worst case engine stops).
The loss of engine power is due to a (A) preexisting vapour lock that has either not been cleared between engine start & application of full power or (B) vapour lock that has developed sometime in the same period.
The vapour lock is not caused by the application of full power on take-off/climb out.
Nor does it relate directly to oil, coolant or head temperatures, except as these contribute to engine heat when shut down.
I would speculate that a very long taxi/hold on a very hot day (40+C), may also result in fuel lock. I have not experienced this and would suggest that much would depend on engine installation/cowling design.
