Yes I was basing it on the fuel gauge. Will need to keep track of fuel
in and distance travelled to get a better estimate. Good advice but
tricky when I am putting in $20 or $40 at a time.

I will check the carb plates as the carboned plugs seem to suggest a
rich mixture. Also, I did notice the fast idle was around 2500 rpm,
which seems a bit high.

Yesterday I let a friend drive the boat, since he has had boats like
this before (it is my first I/O). His opinion was that the boat was
not putting out 190 hp based on how long it took to plane. So whatever
is, perhaps, causing poor fuel economy may also be causing reduced
power. The boat did eventually get up to 50 mph according to the
speedo though.

James wrote:
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.