Need more info........ did it light on propane and then not transition to kero or you weren't even getting the propane "pop"? It sounds like maybe you weren't getting a light on propane and then there was either an increase in propane pressure (shake the can? can not upright?) or there was residual propane hanging around the motor/pipe area and then you got a light.....? (were you starting ***** into the wind?)

If in doubt about unburnt kero in the combustion chamber you can always tip nose down to ground and then tail to ground, run starter, etc.... You could also initiate the start with the manual valve closed and then slowly open it up.