4.3's best gas mileage

Merc4ever

Merc4ever

Petty Officer 1st Class
Joined
Feb 14, 2009
Messages
232
My buddy down at the lake told me your best mileage is in gear, at idle cruising along like a canoe. Is that true?

I argued that from what I have read it's the sweet spot up on a plane with the throttle cut back as much as possible. Seems to me that it would be terrible mileage because you don't go straight when (off plane) weaving back and forth at idle because the boat is not built like a canoe or sail boat.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,525
Re: 4.3's best gas mileage

Merc4ever said:
My buddy down at the lake told me your best mileage is in gear, at idle cruising along like a canoe. Is that true?

I argued that from what I have read it's the sweet spot up on a plane with the throttle cut back as much as possible. Seems to me that it would be terrible mileage because you don't go straight when (off plane) weaving back and forth at idle because the boat is not built like a canoe or sail boat.
Click to expand...

Ayuh,... Donno,...

With my 4.3l, in my 21' tinboat I can troll ALL day on fumes....

Btw,.... Who says ya gotta run Straight,..??
Rules just say ya gotta Get there...;)
 
45Auto

45Auto

Commander
Joined
May 31, 2002
Messages
2,842
Re: 4.3's best gas mileage

Merc4ever said:
I argued that from what I have read it's the sweet spot up on a plane with the throttle cut back as much as possible.
Click to expand...

You're right. Best mileage on a boat will be where the lowest point on the drag curve coincides with the most efficient RPM range of the motor. On most planing hulls, that's just after they come on full plane.

Bondo said:
With my 4.3l, in my 21' tinboat I can troll ALL day on fumes....

Btw,.... Who says ya gotta run Straight,..??
Rules just say ya gotta Get there...
Click to expand...

Yeah, is your goal to take as long as possible to get there, or to get there on the least amount of fuel? ;)


Easy enough to look up some tests on Boattest.com. Here's a typical bowrider with a 4.3L:

SR1-1.jpg
 
Merc4ever

Merc4ever

Petty Officer 1st Class
Joined
Feb 14, 2009
Messages
232
Re: 4.3's best gas mileage

45Auto said:
You're right. Best mileage on a boat will be where the lowest point on the drag curve coincides with the most efficient RPM range of the motor. On most planing hulls, that's just after they come on full plane.
Click to expand...

Ha Ha, Thanks a bunch 45 Auto with your chart it looks like my buddy down at the lake owes me a beer. Idle might be good mileage but not as good as up on a plane and cut back on the throttle!
 
bruceb58

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,478
Re: 4.3's best gas mileage

Depends on the boat and the motor. There was a thread recently that had similar charts with idle being the best MPG. I will try to locate. On my boat with my flow meter/GPS. My best mileage is at around 1000 RPM. My readout is in MPG.

Here is one for an 4 stroke outboard.
248526.jpg
 
P

Pierutrus

Senior Chief Petty Officer
Joined
Mar 25, 2007
Messages
721
Re: 4.3's best gas mileage

Mine just sips fuel all day long. I re-pitched a prop to 22 degree's and I never get out of recommended RPM range, does 4400- 4600. I have gone 4-6 hours at 30 mph and came back with a half a tank!
Open her up with the 4-barrel and all bets are off!:D
 
You must log in or register to reply here.
Top