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Having trouble matching performance of others
- Thread starter Alexander
- Start date
What are you getting for WOT (wide-open throttle) RPM vs. the engine manual's specified range (often 5,000 - 6,000 RPM but not always). I would think that would be the first spec you'd want in order to judge the prop. From what I have read it's best to be in the upper half of that recommended range.
(Maybe you are already fine on WOT and "a step ahead" of this suggestion; I only mention it because not everyone realizes that this is what puts you "in the right gear" on an outboard even if you never actually run at WOT in real cruising life.)
(Maybe you are already fine on WOT and "a step ahead" of this suggestion; I only mention it because not everyone realizes that this is what puts you "in the right gear" on an outboard even if you never actually run at WOT in real cruising life.)
Posting what you get (speed, RPM and fuel flow) would be the first step. Yes, you do want to know what the Wide open throttle, speed and RPM are.
The boats are very sensitive to trim and weight. I noted in one of your earlier posts that you were having a problem with one of the trim tabs. Is that fixed? Also that you have a permatrim and run with the engine trimmed down-that also can be an issue.
How much gear, fuel, holding tank material, water, # people you have aboard is also important.
The Boat Test.com
http://www.boattest.com/boats/boat_video.aspx?ID=931
Is very misleading and unrealistic. This was a very light boat. No water, no holding tank, etc. This boat had the Honda 150 EFI and probably had a stock 15" pitch prop.
We only had the 130 (a considerably less "push" even though rated at 5 less hp than your engine). Loaded, for a month in AK, at sea level the boat would only do about 17 knots--and we had to drop to displacement speeds to get a 200 + mile range, to have a safety factor which we were comfortable with.
The boats are very sensitive to trim and weight. I noted in one of your earlier posts that you were having a problem with one of the trim tabs. Is that fixed? Also that you have a permatrim and run with the engine trimmed down-that also can be an issue.
How much gear, fuel, holding tank material, water, # people you have aboard is also important.
The Boat Test.com
http://www.boattest.com/boats/boat_video.aspx?ID=931
at 3500 rpm. At this speed, you can expect to achieve a fuel burn of 3.8gph and average about 15.4 mph, which delivers a range of 390 miles on a full tank of fuel. She can charge up to 35.4 mph at 6000 rpm with the Honda 150 Four -Stroke outboard. At top end, you burn 14.5 mph and have a range of 235 miles.
Is very misleading and unrealistic. This was a very light boat. No water, no holding tank, etc. This boat had the Honda 150 EFI and probably had a stock 15" pitch prop.
We only had the 130 (a considerably less "push" even though rated at 5 less hp than your engine). Loaded, for a month in AK, at sea level the boat would only do about 17 knots--and we had to drop to displacement speeds to get a 200 + mile range, to have a safety factor which we were comfortable with.
Although this group is far, far better than most, I think that it's a natural tendency for folks to post "optimistically" to forums. I never can sell an item for as much as others claim to have sold their similar item for. I never seem to be able to buy a car for the great price that others report. I don't go as fast, I use more gas, and I catch less fish. I get paid less for the same job and the weather is always better somewhere else. Yes indeed, folks are living large in internet land!
Molly Brown
Member
John! Have no fear, you have a kindred soul in south Florida. Your comment has been my life experience. I do think lots of folks embellish information, intentionally or not. I strive not to do that when I relate my experiences but I am aware that human nature is what it is, and so it can be difficult to really know where the truth really lies. My motto is that the only true reality is the one the individual perceives, accurate or not :wink: Take everything with a grain of salt, besides I like salt!
potter water
New member
My 22 goes about 60 mph on 50 hp and gets about 100 miles per gallon. Beat that!
journey on
New member
Alexander, you are not alone. I can't replicate some of the numbers that were posted here, including some of mine. My comments aren't technical, but based on reality.
And I've come to the following conclusion. A C-Dory 25 is very sensitive to weight. And over the years, Judy and I have learned how to pack more and more on Journey On when we go cruising. So in cruise mode seeing over 2 nm/gal is a thrill, as is cruising at 17 knts.
We just completed an ~500 nm trip, most of it at 7 knts, given the price of gas at marinas, especially Canadian marinas, and it was a good day when we saw 4 nm/gal, even with the current with us.
And I use a 16" prop. The engine isn't going to lug at 2200 rpm and, empty, the prop has give us 25 knts. Didn't check the fuel flow at that speed.
So just accept that what you get is what you get. And powerboats don't get the same mileage as your truck when you're towing that boat.
Boris
And I've come to the following conclusion. A C-Dory 25 is very sensitive to weight. And over the years, Judy and I have learned how to pack more and more on Journey On when we go cruising. So in cruise mode seeing over 2 nm/gal is a thrill, as is cruising at 17 knts.
We just completed an ~500 nm trip, most of it at 7 knts, given the price of gas at marinas, especially Canadian marinas, and it was a good day when we saw 4 nm/gal, even with the current with us.
And I use a 16" prop. The engine isn't going to lug at 2200 rpm and, empty, the prop has give us 25 knts. Didn't check the fuel flow at that speed.
So just accept that what you get is what you get. And powerboats don't get the same mileage as your truck when you're towing that boat.
Boris
Sorry for the delay, we just got back from 5 day shakedown cruise down the coast. Now to the business. We get 5400 rpm tops and about 22 kts, (not mph) fuel meter said 10.3. My trim tab (1 side) is not working but I'm waiting to buy my trailer before dealing with it, so this whole issue may be dumb, but is being done without them for now. The boat was in medium to heavy mode with 3/4 fuel, 25 gal water, 2 people (330 lbs) and gear for 5 days. Perma trim full down to flatten attitude.
I would like to know what prop specs other 25/135 owners are using and happy with. Thanks all of you, I appreciate the help in getting familiar with the new equipment. You really make the learning curve period easier as you know. Bob
I would like to know what prop specs other 25/135 owners are using and happy with. Thanks all of you, I appreciate the help in getting familiar with the new equipment. You really make the learning curve period easier as you know. Bob
Molly Brown
Member
Though I don't own a 25 I do have permatrims but no trim tabs. Still, I believe you will find the "speed" sweet spot if, once on plane, you trim up incrementally, keeping an eye on the speed change. I attain the best speed at a higher trim. I balance that with a desire to run as flat as possible. I only run the permatrims full down in the heaviest of chop. As you will find out, there are many factors involved, most important being the right prop; weight and the distribution of that weight will have considerable impact as well. Also you might compare the height of your engines on the transom with others that have your model. You'll get there eventually. I did run four different sets of props and finally settled on a four blade stainless that we are satisfied with. You'll find that stainless is the only way to go in Florida. They have less flex and don't wear down anywhere near as fast as aluminum. Been running these props for a good 10 years at this point and they are only now showing any appreciable wear.
You may just have a crap engine. Sell it and repower.
When I got my new CD22 in 2008 I powered with a single 90- there are several CD22s powered the same. The performance was crap, the economy was crap- I fought with Honda for 4 years, tried several props (3 & 4 blades), but nothing seemed to help. Honda replaced all of the sensors in the engine, nothing.
We would go out with other CD22s that were powered exactly the same, by the same dealer, and they would run circles around me. I would have to fuel 3 times to their 1.
It was driving me crazy- It got to where I hated going out.
After 4 years and less then 50 hours on the boat, I told the dealer to repower with twin 50s (I had twins 40s on my first CD22 and loved it). The dealer sold the 90 to someone with a smaller boat and put the twins on mine----- I love going out once again- the performance and economy is back to what a CD22 should be.
Don't put all your trust in props alone-- it may be a bum engine-- too bad the lemon law doesn't apply to boats.
When I got my new CD22 in 2008 I powered with a single 90- there are several CD22s powered the same. The performance was crap, the economy was crap- I fought with Honda for 4 years, tried several props (3 & 4 blades), but nothing seemed to help. Honda replaced all of the sensors in the engine, nothing.
We would go out with other CD22s that were powered exactly the same, by the same dealer, and they would run circles around me. I would have to fuel 3 times to their 1.
It was driving me crazy- It got to where I hated going out.
After 4 years and less then 50 hours on the boat, I told the dealer to repower with twin 50s (I had twins 40s on my first CD22 and loved it). The dealer sold the 90 to someone with a smaller boat and put the twins on mine----- I love going out once again- the performance and economy is back to what a CD22 should be.
Don't put all your trust in props alone-- it may be a bum engine-- too bad the lemon law doesn't apply to boats.
I was always pleased with the performance and economy of the 135 Honda we had. Conditions played a part in what we experienced. I used a fuel flow meter to determine best fuel burn for any given condition and RPM setting. Often times, a small adjustment to the trim would result in a more efficient fuel burn... or, if you were willing to go 6 knots instead of 6.3 knots, we would see a worthwhile change in efficiency.
I would suggest you do your own tests after you get the trim tab repaired. I always used the trim tabs at speed, but was willing to trade off a bit of bow down for a more efficient fuel burn. Unless we were cruising and knew that fuel would be iffy, we didn't run with a full fuel tank - no need to carry that extra weight around. Leaving with a full fuel tank and water tank, we would see a drop in economy, and have to use more trim tabs... until we burned off half a tank or so of fuel.
The 25 can haul a load, but we'd leave as much as we could in the truck.
Jim B.
I would suggest you do your own tests after you get the trim tab repaired. I always used the trim tabs at speed, but was willing to trade off a bit of bow down for a more efficient fuel burn. Unless we were cruising and knew that fuel would be iffy, we didn't run with a full fuel tank - no need to carry that extra weight around. Leaving with a full fuel tank and water tank, we would see a drop in economy, and have to use more trim tabs... until we burned off half a tank or so of fuel.
The 25 can haul a load, but we'd leave as much as we could in the truck.
Jim B.
Trimming the bow all of the way down, is not usually the fastest, nor most efficient--except sometimes necessary in heavy chop. I agree with Molly Brown, on trimming up to see what your top speed, RPM are. You keep the throttle set, and trim the engine up. I agree, you need to have both trim tabs working. You want the prop driving the boat parallel to the water, not working to drive the bow down (unless you have to in chop). For some people having the blow slightly up may be disturbing, but if you get better speed, and economy….do it.
At displacement speeds, anything over 6.4 knots is going get get less efficient. For example if you drop down to 6 knots you will be getting better mileage than at 7 knots.
Your speed is a bit better than we got with the 130--even when light. However, we did have a fuel flow meter and did better than that--but I don't know what your consumption was at lower speeds. (As I recollect for the whole 1200 miles for the AK trip, we got about 3 mpg, which includes some longer runs at displacement speeds of 6 knots.
At displacement speeds, anything over 6.4 knots is going get get less efficient. For example if you drop down to 6 knots you will be getting better mileage than at 7 knots.
Your speed is a bit better than we got with the 130--even when light. However, we did have a fuel flow meter and did better than that--but I don't know what your consumption was at lower speeds. (As I recollect for the whole 1200 miles for the AK trip, we got about 3 mpg, which includes some longer runs at displacement speeds of 6 knots.