The engine has fuel injection. I am interested in why it was necessary
to apply full throttle to start it. I understand that fuel injection
should adjust itself? There was some power loss, but not too much.

Fuel injection does not "adjust itself." You need to give it more throttle
because there is much less oxygen by volume at ~6200ft. Opening the throttle
not only adds more fuel (via the injectors), but more air...then it starts.
The adjustment needs to be made because at idle, the mixture is too rich
(too much fuel, not enough O2), and the motor stalls (or won't start). The
power loss is due to an overly rich mixture. Airplanes have a mixture
control that is adjusted as they ascend or descend for exactly the same
reason.

--Mike

wrote in message
oups.com...

RG wrote:
wrote in message
ps.com...
Took my 1995 20' Crownline with Mercruiser 5.7 Thunderbolt Ignition to
Lake Tahoe over the weekend where the air is very thin and had a little
trouble. Could only start the engine by advancing the throttle all the
way. The engine started everytime but stalled most of the time when set
to idle. The engine runs fine at low altitudes. Any suggestions would
be appreciated. Bob J.


It's a common problem with big changes in altitude. There is an idle
stop
adjustment screw on the throttle linkage right at the carb. You'll need
to
turn that screw in a bit to raise the idle stop of the carb. This is
essentially the same thing as keeping a tad bit of throttle applied at
idle.
This will at least allow the engine to idle at high elevations. But you
will still experience a significant drop in power, which will likely need
to
be compensated for by a drop in pitch of your propeller. Also, if you
intend to run at that altitude for an extended period of time, the carb
should be re-jetted for that altitude.

The engine has fuel injection. I am interested in why it was necessary
to apply full throttle to start it. I understand that fuel injection
should adjust itself? There was some power loss, but not too much.