3.7L 180HP (470) fuel consumption

[Benny67]

Question for anyone who might know,

Roughly what's the fuel consumption per hour (@3400 rpm) on a 470 Mercuiser?

Specifically the one with the 4 barrel carb

I know there are many factor at play here but I'd believe someone might have a rough guestimate or benchmark.

Anyone?

 

[Scott Danforth]

most spark ignited I/O boat motors burn 0.4# of fuel per HP per hr

gasoline is about 6.82#/gal

so assuming your commanding 180hp, you would be burning about 10.56 gallons in an hour

if your commanding 100hp you are burning about 6 gallons in an hour

 

[Benny67]

Thanks.

It actually comes close to what I've been calculating through past cruising history with my boat.

I've been just accounting 1gal/mile cruising at 3400 rpm. I know it's better than that but it's a safe amount to count on for average trips.

I was planning a run East up the Long island sound (around 70 miles) and I didn’t want to fill my tank (I'm a cheap bastard) all the way if I didn't have to. This helps me calculate what I plan to do without dumping an extra $100 on fuel that will most likely sit in my tank all winter.

 

[nola mike]

Completely depends on what it's pushing. I get about 4 mpg lightly loaded, 3.5 on a full ship

 

[Scott Danforth]

I was planning a run East up the Long island sound (around 70 miles) and I didn’t want to fill my tank (I'm a cheap bastard) all the way if I didn't have to. This helps me calculate what I plan to do without dumping an extra $100 on fuel that will most likely sit in my tank all winter.

$100 in the tank as prevention is better than a $1100 tow bill because you ran out.

 

[QBhoy]

I’m aware the us gallon is less than the U.K. gallon but I’d be pretty sure it won’t burn anything like a gallon a mile at those rpm. I don’t think anyway. I know that my V8 mpi burns about a litre a mile cruising at 2200 rpm and about 23-25mph.
I will have a look. I’m sure I had a link to a guide. Maybe it does. But unlikely.

 

[QBhoy]

Ok so the 3.0 burns 6.2 gallon per hour at 3500 and the 4.3 about 7.2-7.5 at 3500. Assuming you are on plane at this rpm and maybe a little more at perhaps 20 mph...I might assume you would be a little less than a gallon a mile maybe ? I’m terrible at maths after a few beers

 

[QBhoy]

Oh hell. You might be right. Haha. What speed are you getting at the rpm

 

[achris]

$100 in the tank as prevention is better than a $1100 tow bill because you ran out.

Yep. Had an aeroplane crash on my front yard because the pilot short-changed the fuel calculation...I get it that extra fuel means extra weight and so with an aeroplane, that matters, but with a boat!

...I was planning a run East up the Long island sound (around 70 miles) and I didn’t want to fill my tank (I'm a cheap bastard) all the way if I didn't have to. This helps me calculate what I plan to do without dumping an extra $100 on fuel that will most likely sit in my tank all winter.

Just fill the damn tank and go. An extra $100... You'll spend that on booze and fags. Get over it!

If you're that concerned about fuel in the tank over winter, when you get home, siphon it out and dump it in the wife's car....

Here's what happens when you 'nickel and dime' fuel calculations... (he saved about $20 on fuel, but it cost him the aircraft. They came with angle-grinders, cut it up and put the bits on a flat-top)

 

[achris]

Ok so the 3.0 burns 6.2 gallon per hour at 3500 and the 4.3 about 7.2-7.5 at 3500. Assuming you are on plane at this rpm and maybe a little more at perhaps 20 mph...I might assume you would be a little less than a gallon a mile maybe ? I’m terrible at maths after a few beers

He has 2 of these engines in the boat, so double your calculated burn.

Chris...........

 

[nola mike]

I don't believe that 2 engines will double the fuel consumption, but I still say the weight of the boat will have far more impact than the engine. That said, fill the tank, go for a 20-30 mile cruise, fill the tank. Now you know how much fuel you burn. And bring a couple of Jerry cans. (Wow, way too much thought going into this thread. If you don't know, just fill the damn tank)

 

[Scott Danforth]

BSFC is constant per each engine, if you have 1 engine or 100.....

if you command 100hp, you burn up 100hp's worth


in a few weeks I should be able to see what 450hp does to an 80 gallon tank........

 

[achris]

...in a few weeks I should be able to see what 450hp does to an 80 gallon tank........

At full noise, about 1.5 hours?

 

[nola mike]

BSFC is constant per each engine, if you have 1 engine or 100.....

if you command 100hp, you burn up 100hp's worth

Yeah but a dual engine boat doesn't burn twice the fuel as a single engine at the same speed. You also lose some efficiency, so even though you're using 100hp for 2 engines you use more fuel than 100hp and 1 engine.

 

[QBhoy]

He has 2 of these engines in the boat, so double your calculated burn.

Chris...........

Ah. That’s a good point. Ignore me !

 

[Benny67]

$100 in the tank as prevention is better than a $1100 tow bill because you ran out.

Tow US offers fuel delivery with membership...worst case scenario.

But if I figured out my mileage how would I run out?

The whole point of the post was to get input so I wouldn't run out.

Regardless, I scrubbed the trip due to sloppy seas.

 

[Benny67]

Yep. Had an aeroplane crash on my front yard because the pilot short-changed the fuel calculation...I get it that extra fuel means extra weight and so with an aeroplane, that matters, but with a boat!



Just fill the damn tank and go. An extra $100... You'll spend that on booze and fags. Get over it!

If you're that concerned about fuel in the tank over winter, when you get home, siphon it out and dump it in the wife's car....

Here's what happens when you 'nickel and dime' fuel calculations... (he saved about $20 on fuel, but it cost him the aircraft. They came with angle-grinders, cut it up and put the bits on a flat-top)

Ugh...don't think running out of gas would be this detrimental/dramatic of a situation n my Carver

I'll stick to my calculations and keep the extra money in my pocket for real emergencies