| Author |
Message |
    
william yuchnowicz
New member
Username: gill
Post Number: 1
Registered: 05-2008
| | Posted on Tuesday, May 06, 2008 - 10:11 pm: | 
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Can someone tell me what the fuel usage for a 350 mercruiser on a 22' proline w/a should be about???
GPH???
Thanx |
David R Cole
Member
Username: david_ray
Post Number: 70
Registered: 02-2008
| | Posted on Tuesday, May 06, 2008 - 10:58 pm: |
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Crude rule of thumb for 4 cycle boat engine is about 8 to 10% (in gallons per hour) of its rated horsepower running about 3500-4000 rpm. Crude because of hull design, boat loads, operator habits, etc. |
Rod Stewart
Senior Member
Username: rod_stewart
Post Number: 1251
Registered: 08-2006
| | Posted on Wednesday, May 07, 2008 - 12:33 am: |
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A good estimate of fuel consumption is about 1 GPH per 10 propshaft horsepower.
So if your engine is rated at 260 hp, it should burn about 26 GPH at WOT.
If you are cruising at 3500 RPM, and assuming that hp is roughly proportional to engine RPM, you are making about 3500/5000 X 260=182 hp; and your fuel burn should be around 18 GPH. Pretty nasty, isn't it? And this is steady cruising. If you are stopping and starting like when pulling skiiers and the like, it is much much worse.
There is nothing very economical about pushing a boat through the water.
Rod |
william bannon
New member
Username: gill
Post Number: 2
Registered: 05-2008
| | Posted on Wednesday, May 07, 2008 - 05:42 am: |
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Looks like I can afford the boat but, AT TODAYS FUEL PRICES ,not the gas....18GPH,,,YIKES!!!
Thanx Guys, |
Troy
Advanced Member
Username: troym
Post Number: 494
Registered: 09-2004
| | Posted on Wednesday, May 07, 2008 - 08:54 am: |
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That's at wide open throttle... what are you planning on doing with the boat?
Skiing? cruising? fishing?
My 22' Searay (5.7L merc) burns 10-12 GPH cruising at about 20-22 knots... about the right speed on the way to and from the fishing grounds, depending on the seas state. |
dave_n
Member
Username: dave_n
Post Number: 68
Registered: 11-2005
| | Posted on Wednesday, May 07, 2008 - 11:29 am: |
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Rod, your numbers are very high. A 22' boat with a fuel injected 300HP engine will burn less than 10GPH at cruise speed. |
David R Cole
Member
Username: david_ray
Post Number: 72
Registered: 02-2008
| | Posted on Wednesday, May 07, 2008 - 12:50 pm: |
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Take Mercury's data for a closer estimate. Go to MercuryMarine dot com and pick your power choice. They give fuel consumption data in their test reports so you can get several comparisons, perhaps close to what you want. |
Bert Goodrich
Member
Username: bertg
Post Number: 82
Registered: 10-2006
| | Posted on Wednesday, May 07, 2008 - 04:31 pm: |
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Some of these numbers are way off. I'm not an expert on prop jobs, but the jets I used to run on the rivers up here got around 9-12 gals/hr at around 3400 rpm, with very heavy loads.
JMHO
Bert |
Mike
Advanced Member
Username: mike77cj
Post Number: 133
Registered: 06-2007
| | Posted on Wednesday, May 07, 2008 - 05:07 pm: |
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I'll add my two cents in hopes of easing William's nerves. I have a 1977 23' Formula (4700 lbs dry) powered with a built 350 Chevy (320 hp). I am easy on the throttle and run the boat at 3200 rpm when cruising. I have consistently, for the past five years, averaged 3.85 gph. This takes into account time spent idling at the dock, in the channel and trolling.
Oh, and I should mention at 3200 rpm I am running at 28 mph. Very economical. |
