"Bryan" wrote in message
...
I have a Mercruiser Alpha One carbureted 6 cyl 190 hp motor on my boat.
Should I expect the boat to run normally at Lake Tahoe or will it need a
tune up each time I visit Lake Tahoe from sea level?
I've been told I don't need to alter the tuning if I switch props to one
with more torque when I visit Tahoe.



You will need to do two things when you take your boat to Lake Tahoe.

1. You will need to adjust the idle stop screw on the throttle linkage on
your carburetor. It will be necessary to raise the idle setting so your
engine will idle at that altitude. This would not be necessary on an EFI
engine, but will be required for a carbureted one. Very simple to do, and
just takes a couple of minutes.

2. Assuming your boat is properly propped for sea level, you will need to
drop at least two inches of pitch, and more likely four inches to allow the
boat to operate in the proper RPM band while cruising at Tahoe's altitude.
Expect a very significant drop in overall performance.