Re-Power with what!

Yes that is what I get.
I use 5 gal portable tanks as my boat stays in the water most of the year and it's cheaper to buy at the gas station than at the marina.
It is 45 to 55 min run, depending on weather, to our cabin.
I set the throttle at 4000 RPM and am doing around 24 to 26, depending on the load, and will burn less than a 5 gal can to go up to the cabin and back.
Jimbo
 
Jimbo":3as9kqtc said:
Yes that is what I get.
I use 5 gal portable tanks as my boat stays in the water most of the year and it's cheaper to buy at the gas station than at the marina.
It is 45 to 55 min run, depending on weather, to our cabin.
I set the throttle at 4000 RPM and am doing around 24 to 26, depending on the load, and will burn less than a 5 gal can to go up to the cabin and back.
Jimbo
Click to expand...

I'm intrigued by your gas mileage. I'm not a math whiz, so there may be a flaw in my calculations here somewhere, but here goes:

So let's say the cabin is an average 50 minute run one-way, and you go out and back. So that's 100 minutes of running. At 24 (I'll guess mph) that should be just about 40 miles round trip. Let's say you use 5 (US?) gallons exactly (since most tanks seem to hold a bit more if you fill them, but you are not emptying them completely). Five gallons to run 40 miles = 8mpg... right? That's not 13, but it still seems pretty amazing and nearly double what most people get at those speeds, from what I've been reading. I wonder if it's something about your boat, or your motor, or?
 
jep111":11ef85y9 said:
Canada uses Imperial gallons. US 6 gallon containers are Imperial 5 gallon containers.
Click to expand...

Thanks, good info. I did wonder about that. So re-running the calculation but plugging in 6 (US) gallons (to make it equal to 5 Imperial gallons, if that is what is being used):

So let's say the cabin is an average 50 minute run one-way, and you go out and back. So that's 100 minutes of running. At 24 (I'll guess mph) that should be just about 40 miles round trip. Let's say you use 6 US gallons (equivalent of 5 Imperial gallons) (since most tanks seem to hold a bit more if you fill them, but you are not emptying them completely). Six gallons to run 40 miles = 6.6 mpg... right?

That would only be about half as much as the 13mpg you were thinking -- have I made a math mistake? (Not at all unlikely!). That would still be about 40% better than most people are reporting (which is about 4.5, right?) I would certainly be very happy with nearly 7 mpg.
 
My boat typically gets 4-6 mpg. And that is on its best days...... With over a 1200 hours on it, it goes like this: 18-22 mph = 5-6 mpg, 24-27 mph = 2-5 mpg, faster = really bad mpg, chugging around at 3 mph, it gets around 8 mpg.

My honda 45s run perfect and I don't ever see getting any better. If I could, it would be super.
 
Sunbeam,

There is nothing wrong with your math; it's just being built on fuzzy assumptions. Determining distance by time and speed leads to real problems when you're dealing with fluids (either in a boat or a plane), and there has been no indication how speed is being determined (water wheel, pressure tube, gps, etc).

Until someone gets a chart and dividers or keeps a gps log while they track fuel burned, mpg on a boat is a fuzzy statistic at best. I wouldn't worry about it; if Jimbo's method is good enough to keep him from running out of fuel on the way to his cabin and back, they're good enough.

Cheers!

John
 
Agreed that we don't have exact figures. I was just "doing the math" because, when I see a "story problem" like that, well, I want to turn it into numbers :) OTOH, I probably would not have bothered if 13mpg had not sounded so amazing (and so desirable!). Anyway, it sounds to me like the mileage is probably in the general realm of normal, if maybe slightly superior (I think I would be re-powering for double the mileage).
 
Was offered just $2500 for my DF70 on a trade in for a Yam F90, not a lot of money. To put out $10,000 for a new motor when i have one that runs great doesn't make a lot of sense. My fishing buddies. ( both outboard mechanic's ) . think i should wait until something major happens to the motor before i even think of repowering . A new Yamaha F90 would sure look good on my boat but i guess i can wait. Tug
 
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