Hi Barry,
> 1500 ft elevation & 36 deg C temps. I had to taxi through long grass
> at quite high power to get to a short tarmac runway. Take off roll
> was fine and only when I was in the air did the stuttering and power
> loss begin. Luckily the glider site is on a hill so I could get up
> some speed descending into the valley. She stuttered her way up to
> about 1000 ft above the field and I waited to see if the "vapor lock"
> would clear but after 5 mins landed again to change my pants!! There
> was no pressure loss, or at least my warning lamp did not come on
> which is quite sensitive.
Must have been a scary experience!
Do you have a 914? The only correct way to measure fuel pressure in that
case is to measure relative fuel pressure, i.e. fuel pressure compared
to airbox pressure. The 914 has no "static" fuel pressure. Sufficient
fuel pressure for a low throttle setting may be insufficient for higher
throttle settings.
> time!! I searched for the problem for a month before in frustration I
> wanted to measure the fuel flow from the pumps and found that about
> 50% of what was coming out of the fuel line at a carb was air!! I had
> no obvious fuel leaks but air was getting into the system.
Are you sure it was air? I had the very same problem and spent almost a
whole frustrating day searching for the air leak. There wasn't any, the
bubbles where fuel vapor bubbles, which form inside the suction line and
fuel filter due to the pressure drop caused by the fuel pump.
> I changed
> all the fuel hoses (Europa originals), re-routed them with
> insulation, changed the clips and no more air.
Maybe it was a colder day, or different fuel...
> I am still not sure
> that it was a vapor lock on that day but it certainly made me re
> think my fueling strategy. I now always fill with Avgas when the
> temperature is approaching 30 deg C or bellow 0 deg C.
Well, most of my flying is at higher temperatures or at higher
altitudes, so this pretty much bans the use of mogas unless I solve this
problem.
Frans
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