Fuel burn question.

[McGillicuddy]

Originally Posted by CHANCE1234

Denny, again an awesome reply. It will take me many reads to digest all the info you provided but I will do it. My av plate is 1 inch above the keel. I'll take a look tomorrow while running and also try to set a trip gauge on my gps and monitor cruising rpms and knots. I swing a 13 3/4 X 15 merc prop from,west marine. I'll look through the book tonight for wot and optimal.

If you're running the Quicksilver Black Diamond, I think that's about as good as its going to get unless you ante-up for the stainless version, the PowerTech MQF3 or 4. I may be mistaken but I believe yourl motor was known a 2+2. Designed for bass fishing circuit, it used a funky cylinder/carb deactivation where in idle it would burn on top 2 cyls, and when it hit around 1800 rpm, the lower 2 would kick in and it would take off. Kinda no mid-range slow putting - slooow or GO! Sloppy idle but nice at cruise. It's very possible that the carbs could be re-jetted for better efficiency with modern fuel. 2.07 gear ratio I think, 5200 rpm target should be about right w that prop.

Glad you got good insight on the vent burping issue -- good call, y'all.

I use a Navman fuel meter, very similar to Lowrances current version to keep me in the loop on fuel, but a 6 gallon portable tank should get you to P'town easy. Might be worth rigging just to see if your motor is burning right. I think you should see over 3 mpg overall as that idle burn with 2 cyls. should be much better than what I could ever hope to see in my I-6.

Lots of god stuff coming out of this post. Thanks, and good luck