On 26 Apr 2006 20:48:16 -0700, "nrp" wrote:

Jay Honeck wrote:

I've never heard of what you're talking about before. Are you saying
that mogas starts to go bad after a WEEK?

If I don't purge the float bowl, starting cold w mogas is less
predictable, and a bigger slug of fuel will puddle and remain in the
intake manifold after startup. This slug goes thru the engine with a
lot of burping & coughing etc as the throttle is first advanced after
starting. I consider this tacky. I don't like flying behind engines
or with pilots that don't start well - just on general principle.

This doesn't happen if the engine is warm as the oil heats the manifold
which minimizes fuel condensation.

Mogas has a wider distillation temp range than a/c fuel. The light
components of mogas will more easily evaporate from the bowl leaving
you with a more-like-kerosene mixture for starting, depending on how
long it has been sitting. Yes you can usually get things going, but it
does mean grinding the starter more.

In the fifties farmers would burn something we called "Powerfuel" in
their carburated tractors. I worked in a garage & we could never get
them going without priming with fresh gasoline.

My lawn mowers like this too. Especially my snow blower. Can aircraft
be far behind?

Thanks that makes a lot of sense. I've aways found my engine 0-290D to
be harder to start with autoffuel than 100LL even though it runs much
better on it. I amost always have my engine stall after about 20
seconds during a cold start regardless of priming or throttle pumping.