Reid Vapour Pressure [RVP], relating to New Zealand & other countries including the U.S.;

In the link you will find some very interesting info which, to me, concludes that the appearance of baffling hard starting or vapour lock could happen because of the seasonal fuel you have in your tank at that particular time.

With todays climate upheavals, the fuel suppliers must be spinning a roulette wheel. Very confusing!



Butane is the component controlling vapour pressure & therefore vapour lock. In the charts you will find there are no less than FOUR seasonal fuels.



<http://www.med.govt.nz/ers/oil_pet/f...513_152909>



Brian NZ