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.