expected milage per gallon

tpbrady":3hsxhrkm said:
Steve,

Are you sure you are running a 19 pitch prop on the Honda? That is pretty steep. I have gone through 4 different props and have settled on the 14 pitch 3 blade Quicksilver stainless steel. The new Honda is real sensitive to engine loading in getting the best fuel economy. With a 17 pitch I could hardly get 3 mpg. With the 14 pitch prop I can run heavy at 4500 rpm at 15-16 mph and get 3.4-3.5 mpg. As I lighten up the economy improves to around 4 mpg. Pushing it faster than that drops the fuel economy. This is running without the Permatrim. With the Permatrim on, I can run at 12 mph 4100 rpm and 4 mpg heavy but any faster and economy drops quickly.

With the 14 pitch prop I can spin up to 6300 rpm easily without full up motor trim and reach 30.5 mph.
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I think Steve has a 90 Johnson which is the same as a Suzuki (I think). The Suzuki should spin more prop than the Honda as it's geared lower but I think 19" would be to much unless the boat is really light. Mine came with a 17" aluminum which was pretty good.
 
When we had the Duck cd22 cruiser with 90 suzi with 14/18pitch she would tach out at 5800rpm and give us about 34-35 mph we then put on a trim tab from Bob's machine in tampa similar to permatrim we would get about 32-34 and we would get about 4.4-almost 5mpg statute This is at sea level with a lot of idleing speeds .Now with the cape cruiser witha f115 with 13by15pitch we get similar mpg witha lightly loaded boat This is done witha garmin 498 gps and a navman 2100 fuel mgmnt system .we usually run tanks down( 60gallons ) to about 20 gallons or so this is when our yamaha gauges are showing almost empty when we fill up it averages out to 4-5mpg depending on use .when we tube and just go out and cruise we are at about 3.8-4mpg but just going out to the beach and going slow we get about 5mpg. we do use a fuel injector cleaner and change all the fluids and filters every 100hrs about 6-7 months .we have owned the cc-23 for over 1 year with 500hours on the motor 210 from me the yamaha is unbelievable fuel economy
 
I have twin Honda 40's on my cd22 cruiser, and averaged 3.75 mpg over 7500 miles (http://smittypaddler.com/cds/cd4/greatloop/index.htm). I noticed a boost of about .5 mpg when I switched from the original aluminum 13-pitch propellers to Piranha propellers (www.piranha.com). The piranha's are lighter and have a slimmer profile. It's also great to replace only a single blade when it gets dinged, at a cost less than $20, without having to replace the entire propeller.
 
Yes, Marvin is correct. I have the Johnson 90 which is the same as the Suzuki and has different gearing than the Honda.

With the 14x19 I can reach about 5200 to 5400 rpm WOT. The manual indicates it should be 4500 to 5500 so I think I am in the right spot. As I said this prop came with the boat for EQ.

I also have the Piranha 4 blade prop with the 14x18 blades and the 14.5x16 blades. I have not run the 14x18 blades a lot but it seemed I was getting worse mileage with it. Probably need to test it again.

The 14.5x16 blades worked much better than the 3 blade 14x19 when we were on lake Yellowstone at 8000 ft. Not sure the mileage was very good but the boat would get on plane faster and it did not feel like it was lugging.

Steve
 
The title of this thread is "expected" fuel mileage. I'll bet that most people are out there reading statements like Jim's that he goes 35 miles an hour and gets 5 mpg are scratching heads and wondering what they are doing wrong, because in the real world, numbers like that are not achieved by most people most of the time, no matter what engine and prop they use. It isn't just finding the right prop, it is everything: prop, load, speed, current and wind. So don't be disappointed if you get 3.5 mpg on your CD22 on average - you are not necessarily doing anything wrong. You might just have been running fast against the tidal current for most of the way.

You should be planning for the WORST mileage you are likely to get, not the best, in your trip planning anyway. On our CD25 I may get 3 mpg at normal cruise speed (typically 15 - 17 knots) but I plan for 2 mpg. If you want really phenomenal economy, it is really simple: slow down to about 6 knots!
 
We have a Cape Cruiser 23 like Jims but with a 135 honda. On our loop trip last year we averaged 4-5 NMPG cruising at 4400 RPM at 25 knots. From this thread these numbers sound to good to be true. I'll check again next time we're out.
By the way Scalloping was pretty good this past weekend at Port St Joe. We made our escape sunday AM before claudette paid us a visit.
Alan on Simplicity
 
Just an aside. I don't believe mileage quoted if it's only from the fuel flow meters. I think those are often miscalibrated a little. A well calibrated meter has a very low error rate but calibration can be dependent on a number of factors (like temperature) that are not well controlled. What I believe in is measurements averaged over a couple of tanks of fuel where you keep track of distance over the ground and actual fuel that went in.
 
Pat I never get 5mpg going 35 I usually run around 4200rpm -4400rpm sweet spot on both engines 18-22mph .Also around SW florida there are lots of slow no wake zones so mileage goes up considerably when you obey the signs . Also a lot of boating is on the intercoastal .less waves and swells to deal with.I guess my boat is not weighted down like some of the c-brats. We use the boat for mostly day trips so it's pretty light. I/ve gotten the same mileage out of both boats I've owned .I think the difference is the weight and maybe stronger tides out in the PNW I;m not complaining just some observations over the last few years of ownership.
 
Roger,

I agree on the fuel flow meters. Mine has been in service 5 years now and is to the point where I need to replace the transducer. On my outing this weekend, we covered 80 miles on the first tank and put in 23 gallons. On the second tank after we lighter, I covered 31.9 miles and put in 8 gallons. Sea conditions for 30% of the first tank weren't to good. 3 foot seas with occasional 4's on the port bow and then running with them for a couple of miles. The second tank was on calm seas.

The most important factor I see is weight in most sea conditions. The second is sea conditions. I do worse in following seas because there seems to be more uphill than downhill.
 
This thread reminds me of the old story of the guy who bought the VW bug and his neighbor kept adding gas to the guys gas tank for a month and the guy was raving about his gas mileage. Then the next month he started syphoning gas off so the guy thought something was wrong with his car. I kept pretty good track of my fuel usage over about 500 miles not with the flow meter and got consitently 3.8 MPG figured with actual fuel used not flow meter. There are so many varibles that it's hard to compare boats and quite frankly for me if I worried about it it would take away from enjoying the boat. On the other hand it's good to know what your normal fuel burn is so if it drops off dramaticly you know something is wrong. Now I'll probably sing a different tune if it goes back up to +$4 a gallon :)
 
06 carbureted Honda 90

My 2 cents:

Only time I use my motor tilt (with Permatrim) is when I’m either coming up on plane or headed into heavy chop, or in heavy falling seas in which case I lighten up on the tabs and apply down trim with motor. Normally when I get the RPMs to 4200 the motor goes level trim and the boat picks up about 1 or 2 mph, optimal trim on tabs is 80% extended; any other combination produces negative results.
My buddy and I put 180 miles on the boat this past weekend in 28 hours, most of the time running at 4800 to 5100 rpm when possible. On return trip from fishing we had an 85 mile run to port, I wasn’t concerned with fuel economy. In the end we averaged 3.6 mpg using 50 gal, I was pleased because when encountering heavy chop I just gave it full down trim, motor/tabs, and poured the coals to her.
Average high cruise was somewhere around 21 to 22 mph, last 6 miles after picking up shrimp pots it was WOT to port at close to 27mph…had to make the 8:00 evening tunnel.
Don't have a fuel flow meter, other things more important.

Nice jag of shrimp and Halibut, but a brutal trip otherwise, won’t to that again….at least not tell next weekend.
 
We now have 100 hrs on each Honda 50. I'd say 85% of the time we will run at Trawler speeds (around 6kts) and we'll lift 1 of the motors out of the water. I'll then use the Honda Fuel Meter (Honda Speedometer) to determine the speed that we want to go, based on the amount of fuel being used. I find that I can go from 5.4 kts to 5.2 kts and save 15% on fuel usage (according to the Honda Fuel Meter). Because we love going slow, I'll try to use less than 1 gallon per hour.

For the most part with 1 engine we will get around 6mpg.

When I have both engines running, it seems like any "fast" speed and we'll get around 2.7 mpg - almost no matter what - full throttle or just on plane.

I'm happy with our mpg - especially with just one engine down (sometimes it'll be in the 8 - 9 mpg range), but I'd like to have a bit more with both engines down.

We have both permatrims and trim tabs, which I try to adjust to maximize the fuel.
 
I have experimented quite a bit with speed, props, and trim. I have Permatrims on twin Yamaha 50's, with aluminum 11 5/8 X 11 props. I don't have trim tabs. In good water at the boat's sweet spot (20-22 mph, 4400 to 4800 rpm, and modest up trim), I can squeeze 4+ mpg according to the fuel meter. At 6 mph I can get almost double that. But I don't think the fuel meters are all that accurate at giving instantaneous readings, especially at very low speed, and mileage will vary wildly based on conditions. (The meters estimate of fuel used over the course of burning a whole tank, on the other hand, is very accurate.)

In the real world, independent of the fuel meter readings: One trip of just about 2000 miles in a heavy, heavy boat under varying conditions used just about 600 gallons. And based on 3+ years of experience, I'd say the high side of 3 mpg is about what I get overall.
 
Simplicity":3j85yqkx said:
We have a Cape Cruiser 23 like Jims but with a 135 honda. On our loop trip last year we averaged 4-5 NMPG cruising at 4400 RPM at 25 knots. From this thread these numbers sound to good to be true. I'll check again next time we're out.
By the way Scalloping was pretty good this past weekend at Port St Joe. We made our escape sunday AM before claudette paid us a visit.
Alan on Simplicity
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Hello Alan,

What prop are you running on your Honda 135?

With a SS 3 x 14.25 x 17 on my Honda 135/CC23 I'm getting 3.8 mpg on 50-60 mile (roundtrip) fishing trips consisting of mostly 4000-4500 rpm (yielding 20-25 mph) runs out to the reef then 3-4 hours trolling at 4-6 mph.

thanks,

/david
 
Hi David- The Honda has an aluminum 15x17 on it. I need to check my mpg again next time out but one possibility might be that the Cape Cruiser is lighter than the Venture even though the hull shape is the same. How has the offshore fishing been lately?
Alan
 
Dave- just realized you also have the Cape Cruiser so no weight difference-I'll check mpg again ext time out. Alan
 
Simplicity":cyk0513d said:
Dave- just realized you also have the Cape Cruiser so no weight difference-I'll check mpg again ext time out. Alan
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hello Alan,

Right, our boats are virtually identical...right down to the color, I think :?:

My boat also came with the Honda Aluminum 3 x 15 x 17 which works fine. I wanted a SS prop...Honda apparently doesn't make a 15 inch dia SS prop but only 14.25 and 15.25 dia...I ended up buying the 14.25 dia which seems to work fine too. With it, I've gained a couple WOT mph and need 200-300 more rpm to cruise (i.e., to cruise at 20 mph I now need, say, 4300 rpm where it was 4000-4100 before with the larger aluminum prop). These results are with a load consisting of 4-5 people, cooler, fishing gear, full fuel and water. Sometimes there's even a fish in the cooler...

If my 'boat improvements' cash wasn't used up for the year, I'd like to try the SS 3 x 15.25 x 17. I don't care to run my boat at over 5000 rpm; with the current SS prop WOT yields 5600-5800 rpm. Things get scary at that speed! My Honda 135 really likes to run in the 4000-4500 range for cruising, so maybe swinging a little larger prop would be beneficial?

Anyway, I suspect if I could ever cruise at displacement speeds long enough to check my mileage, I would be over 5, at least that's my hope. But with teenagers on board, they frequently feel the need for speed whilst at the helm...heck, it gives me the rare experience of riding in the cockpit with my bride :lol: ...cheap thrills

/david
 
David- With the stock prop & WOT we get about 5200 RPM. She seems to like 4400 for cruising and GPS says 25 knots .Of course on the loop trip when we checked mileage occasionally it was mostly just me & Linda. I imagine 2or3 extra people can make a difference. Good luck with the fishing. Alan
 
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