wrote:
Chuck,

Where did you get your fuel consumption numbers? They are a bit on the
low side in my experience. The normal rule of thumb for gas engines,
which I've found to be pretty close, is 1 gph for every 10 hp. At 3400
RPM most engines, properly propped for the boat, will run at about 50%
of maximum rated power. That would put the 350MPI at 15 gph and the
496 HO at 21 or 22. I have neighbors with both engines and that's in
the ballpark for what they are seeing. My old 350 4bbl rated at 260 hp
has always burned right around 13 gph at 3400 cruise.

The carbed 350 in the Mercruiser chart is a 2 bbl, not a 4 bbl, and the
9 gph is at 3000 RPM vs.your observations at 3400.... 9.0 gph for a 2
bbl operating at 3000 vs. 13 gph for a 4 bbl operating at 3400 probably
represents as much difference between the two figures as would be
believable- but I don't think the difference defies credibility.

Other differences between the "dock talk" numbers and the Mercruiser
figures may (possibly) be due to MPI or other advances in engine
technology, may be influenced by the fact that the Mercruisers tested
by Mercury Marine will typically be perfectly in tune, and results from
controlled tests will undoubtedly vary from horseback estimates made by
boat owners. Most boat owners may not be actually running at a fixed
RPM for an extended period of time and many are probably not using a
fuel flow meter.

Mercruiser is a Brunswick product, and the fuel consuption data is from
a sales borchure for another Brunswick division.

Can you accept attachments at your hotmail address? If so, I'll scan
the page and email it to you.

Can you accept attachments at your hotmail address? If so, I'll scan
the page and email it to you.

Yes, attachments are no problem.

My 350 burns about 9 gph at 3000 RPMs also. Probably it is running on
only 2 bbls at that speed.