Gas mileage on sundancer 268 with 454 7.4L mercruiser

Nov 3, 2017
109
Syracuse, NY
Boat Info
1988 268DA Sundancer Single 454
Engines
454 7.4 L Mercruiser Alpha one
I just took a 60+ mile trip and I think I got 1.68 mpg. I would say I was running on plane maybe 7 percent of the time. Does this sound about normal? I did use the trim tabs and power trim to maximize.... Slow speed was around 1400 room, fast speed about 3400 rpm.
 
All of those numbers sound about right Jack.

At 3400 you are just cracking the secondaries open.

A 16x16 prop will keep her on place at lower RPM's and give you a little better fuel mileage.
 
Last edited:
Thank you for that
All of those numbers sound about right Jack.

At 3400 you are just cracking the secondaries open.

A 16x16 prop will keep her on place at lower RPM's and give you a little better fuel mileage.

Thank you for that advice my friend.
Nobody said boating would be inexpensive. Good news is, the boat runs great and I am very confident in her.
Jack
 
That is all that matters! Mine runs like a Swiss watch, and each trip costs me the same $$ as a Swiss watch...LOL.

Now the guys with 390's and twin 454's will chime in and call us light weights...hahahaha
 
That is all that matters! Mine runs like a Swiss watch, and each trip costs me the same $$ as a Swiss watch...LOL.

Now the guys with 390's and twin 454's will chime in and call us light weights...hahahaha


Ok so I'll oblige as a 390/454 owner. .6mpg is the norm at cruise. 1.1 mpg at hull speed. It is what it is.
 
I had a 87 250 DA with the same 454 Magnum and the Alpha 1 outdrive. I figured 1.25 per gallon, but I never really wanted to know. I made a lot of short trips over many weekends and what mattered is only filling it up twice or three times all season long! I had a full crew of 4, plus a Golden Retriever and a lopsided asshole (Lhasa Apso) onboard along with a kayak for a weekend away. Usually we had an additional friend or two that accompanied us as well.
 
Yes, gas is over 4$ here (and that was before the latest uptick, not sure what it is now!), so a trip we have planned in August, about 200 miles round trip, will cost close to 900$ in fuel alone, getting .9mpg. But, money well spent for a 4 day cruise.
 
Do you have the part numberfor the 16x16 prop what prop do you use

I'm not sure what prop is on my boat, I do know it is chipped up so I'm going to put my spare prop on while Tom changes the bellows and gimbal bearing.
$840.00 sound fair? That's his price....
Oh well.
Does anyone know how to tell what the pitch is on a given prop????
 

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I'm not sure what prop is on my boat, I do know it is chipped up so I'm going to put my spare prop on while Tom changes the bellows and gimbal bearing.
$840.00 sound fair? That's his price....
Oh well.
Does anyone know how to tell what the pitch is on a given prop????

Jack,
If you can still read the numbers stamped on the prop, the first number is the diameter, the second number is the pitch.

example: 15X17
 
I'm not sure what prop is on my boat, I do know it is chipped up so I'm going to put my spare prop on while Tom changes the bellows and gimbal bearing.
$840.00 sound fair? That's his price....
Oh well.
Does anyone know how to tell what the pitch is on a given prop????
Not bad if that's parts too if I remember correctly you have an alpha 1 drive and if so you should be getting the water pump impeller as well as lower shift cable done at the same time. I did this job on my last boat and it is a lot of work but all important especially on a new to you boat. You should be good for a few years after this as long as you never start or even crank it over while not in the water or with muffs hooked up. If you buy muffs get the type that have rectangular rubber muffs and supply water to both sides
 

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