Fuel vs Range

[LuckyPenny]

I have just purchased a 1977 Winner 5.7 (mercruiser 250) 24 foot Family Express. At cruising (2000-2200RPM or so) what can I expect for MPG or GPH? Also, from the experts what would be the most comfortable and fuel saving speeds be?

 

[todd5881]

Re: Fuel vs Range

if it has a 4 barrell carburator, as long as you keep the 4 barrells closed at cruise you should do ok with the gas milage! However all engines are different! depending on how well they were taken care of, also if they have had the plugs replaced or not. There are alot of factors that can effect fuel usage, you will just have to see how it does and then go from there if you are not happy with fuel usage, also it depends if the water is smooth or choppy, if you are pulling skiers or anything, to many factors to really know what it will get as far as fuel usage goes!

 

[Dunaruna]

Re: Fuel vs Range

Luckypenny, you need to find your cruising 'sweet spot', thats when you are content with the speed and ride comfort and hopefully have reasonable fuel economy. Sometimes this can be achieved before the secondaries kick in (Todd, thats what you meant right?)<br /><br />As todd said, many factors effect fuel economy but prop selection and correct tuning are the big ones. Have a read of the prop FAQ at the top of the index page - a good starting point.<br /><br />Your doing well if you can cruise at 2200rpm, is that on plane?<br />Aldo

 

[sealyons]

Re: Fuel vs Range

If you are using/ storing the boat in salt water make sure that your bottom is free of barnacles and other creatures. That can slow you down and eat up your feul economy considerably.

 

[cc lancer]

Re: Fuel vs Range

If you are going to run in the river, you may want to come up on the RPM's, your boat is going to be lugging at 2 to 22, my best spot is 2800.<br />Play with the trim, you will find the best position, with load, water, and other factors.

 

[LuckyPenny]

Re: Fuel vs Range

Thanks so far. What I am interested in is for a benchmark, assumed the hull is clean, and she is trimmed out correctly, the engine is tuned, what can expect for fuel useage (either miles per gal or gal per hour)<br /><br />Thanks

 

[Doug Durako]

Re: Fuel vs Range

Newer boats are lighter and use 4 to 8 gallons per hour through at cruising speed.<br /><br />Your boat could be double that, depending on weight, hull design and draft (how deep she runs).<br />If it pushes a lot of water, like a barge, it'll suck the fuel.<br /><br />My guess is you will use 8 gallons per hour or more.

 

[Doug Durako]

Re: Fuel vs Range

One more note--is your tach correct? I would not think a 24-footer would even plane at 2200 rpm. I would think it would take more like 3200 to keep that thing out of the water???

 

[cuzner]

Re: Fuel vs Range

My 1994 sundancer (aft cabin) planes at 2500 rpm, the sweet spot is around 3100 rpm.5 L mercruiser with a 17p prop speed around 28 mph on gps.<br /><br /> Jim

 

[airman]

Re: Fuel vs Range

Go to www.boattest.com You will probably find something to compare to there and they've got all the numbers you could want.