One other thing to mention is that the tachs don't agree. When the port
engine tach indicated 3200, the SB tach indicated 4000, with the engines
synched. It may be that both are reading high and we weren't actually
running at cruising rpm, but given the throttle positioning and engine
sound, it did seem like the engines were around the 3000 rpm range, so I
chose to believe the lower tach, as did the boat owner.

The bottom is very clean. The boat is kept in dry storage. The trim tabs
work properly. The props are in very good condition, which makes me think
they may have been replaced at some point, and may not be optimal.

And no, Rob, the anchor wasn't down, although it almost felt that way I
can promise you I won't be buying this boat until/unless I get to the bottom
of this.

Steve

"Steve Helling" wrote in message
...
I recently did a sea trial on a boat I'm thinking about buying, a 1990
Thompson 288 Adventurer flybridge cruiser with twin 350 mercruiser
inboards.
I was disappointed to find that at 3200 RPM, trimmed for max speed, it
could
only make 13-14 knots, as indicated by GPS, and at WOT, around 4800 rpm,
it
topped out at about 24. This was in glass-smooth protected waters with
little wind. The engines seemed to be running fine, but this seems a
rather
slow boat. It's my understanding that much over 3200 rpm the 4bbl carbs
open up and send fuel consumption through the roof. Any thoughts or
advice
for this beginner?

Steve