Vapor lock question????

wise purchaser wrote:
Have a cessna 150 with 150 HP conversion. I burn regular mogas for
the most part. My bird can tanker up to 60 gallons so I have very
long range capability.

Wow, even with mogas you double the value of the aircraft by filling
up :-)


The plane runs fine on the mogas not to mention the SAVINGS! Avgas
here is running as much as 5 bucks a gallon! car gas runs about $
2.45 gal

It actually runs better on mogas. 100LL is not particularly low in
lead compared to anything other than the 100/130 it replaced. It's
got 4 times the lead that the old 80 grade did.

Since the airplane is gravity feed ( the engine has a engine driven
fuel pump) could I have a problem with vapor lock?? What would be
the indications of the lock? at what point could i expect vapor
lock?? start up? takeoff!!! ???

You're not likely to see it. One of the criteria for getting that
STC is to flight test for the conditions condusive to vapor locking.
Most commonly they are high ambient temperatures and very low fuel
flow rates, low pressures. In my plane (not approved for avgas) the
worst case
is a hot day, shutting down for 30minutes and letting the fuel
boil inside the lines not moving and then try to restart.

Can't vouch for 150/152's but the 172 does have a small locking
problem which was responsible for the suggestion at high altitudes
that you use LEFT or RIGHT rather than both to increase the fuel
flow rate.