Are you basing this on the fuel gauge? If so you need to measure based on
how much gas you put in it. Fuel gauges are notoriously inaccurate on
boats.

I agree with checking the timing. There are not any high speed or midrange
mixture adjustments on your carb. The main thing to check is to make sure
the choke plate(s) are coming fully open. If you have to dig further into
the carb the next thing to check is that the float valve is working
properly.


"Inno" wrote in message
ups.com...
I've had my "new" 99 Larson LXi 186 out for two weekends now and cannot
believe the gas consumption. At around 25 mph it uses about half a
tank per hour! I think it works out to around 2 mpg!!! I expected at
least 5 mpg, and even that would not be impressive.

I have changed the plugs since last weekend as they were a little
carboned up, but not bad. Can't see any improvement in fuel
consumption. I am planning on getting a mechanic to look at timing and
carburetor settings.

Anything else that folks can suggest I look into myself before that?
The boat has been lightly loaded and I think I am not messing up the
trim too badly, after getting some advice here.

TIA.