Is it worth up grading
- Thread starter Conan2324
- Start date
Conan2324":1e1yt7hg said:
You want to add 20 mph or cruise at 20 mph?
My '08 CD22 will do 20mph easy with a Honda 90 (about 4K rpm depending on the load) when loaded for being out for a week or so.
The 22 starts getting squirrelly at speeds above 30 mph. Going faster than that is not recommended.
Unless there is something wrong with the existing motor or you regularly travel with a heavy load I'm not sure how much you'd really gain with a new motor.
Agree with ssobol. You will see little difference in top speeds. Unless that boat is very heavily loaded or is at exptreme altitude (degrades by about 3% per 1000 feet. So 100 hp at sea level will be about 90 hp at Lake Powell (3500') and 80 hp at Yellowstone lake. '
I would only change the engine if it is "worn out"--and for a well maintained Honda that can be a long time.
What is your RPM at WOT? What RPM at 20 knots? Prop Change is often your best bet.
I would only change the engine if it is "worn out"--and for a well maintained Honda that can be a long time.
What is your RPM at WOT? What RPM at 20 knots? Prop Change is often your best bet.
Earlier today, I was looking at your post and wondering what weight/load you run normally with your C-Dory. With your normal use, are you able to keep the rpm between 5000 and 6000 rpms? If so, you are properly propped for your boating use. If not, I would try a smaller prop because you may be overly propped. You have a great motor with your Honda 90 and size wise, it is actually what C-Dory recommends as the smaller size motor on a C-Dory 23 Venture.
colbysmith
Active member
FWIW, I had a Merc 115 on my 22. During past Meet in the Middle gatherings, it seemed like many of us ended up racing on the way back from a day outing. I did outrun the 90's. But not by much. So I would say unless you are just looking to push or pull a heavier load, I don't think you are going to see but only a few mph more. BTW, the 90's seemed to get better fuel mileage than my 115. Colby
Donald Tyson
Member
I have twin 40's. I generally cruise @ 19-20. 80 horse is all. Goes 26 all out. Playing with props is cheap compared to switching out engines.
Conan2324":289loa6p said:
That's the prop I run on my 90. 15mph @ 5K seems pretty low. I get around 20mph at just above 4K rpm. At WOT (5.6K rpm) my boat will do about 35mph if it is light (but it's pretty scary at that speed, the hull is hanging onto the water by a thread).
Are you running very stern heavy? Do you have trim tabs? Have you weighed your boat with a typical load on it?
You might check the mounting height of your engine. I think engines are quite frequently mounted too low. You should also think about installing a Permatrim on your engine if you don't already have one (or similar foil). I installed Permatrims and raised my engines a notch so that just the thinnest film of water flowed over the top of the Permatrims when the boat was planing. Speed and fuel burn both improved.
starcrafttom
Active member
Also check o see if you hub is slipping. The rubber between the prop and the shaft is designed to give if you hit something. some times it starts to slip but not completely. so you are not getting a full turn of the prop for a full turn of the hub. unless you are really heavyly loaded you should be getting better performance.
Something is defianately wrong. I have had 90's on both my C Dory 22's, and 30 mph was max at WOT, with the 15" prop. SS will give better numbers but by not a lot.
I also had the experience to have a boat with no foil and no trim tabs, then a boat with trim tabs, to which I added a Permatrim. To get the most out of these little boats, they need the engine at the correct height, trim tabs on the boat and the Permatrim. Initial design was with a "flat iron" Dory bottom, and a 70 hp 2 stroke, much lighter. With the addition of some variable deadrise, and the reverse shear at the chine, the boats became more suited for higher HP--but most still had the lighter weight engine. Adding the tabs and foil, help to compensate to the additional weight we add to the boats, and make them better running.
I also had the experience to have a boat with no foil and no trim tabs, then a boat with trim tabs, to which I added a Permatrim. To get the most out of these little boats, they need the engine at the correct height, trim tabs on the boat and the Permatrim. Initial design was with a "flat iron" Dory bottom, and a 70 hp 2 stroke, much lighter. With the addition of some variable deadrise, and the reverse shear at the chine, the boats became more suited for higher HP--but most still had the lighter weight engine. Adding the tabs and foil, help to compensate to the additional weight we add to the boats, and make them better running.
I do not know if you trailer or keep your boat in the water. One thing not mentioned above is that if boat is kept in the water; Marine life growth on the bottom of the hull could cause performance to be that bad. If the hull is clean, then I agree with all of the above suggestions. -Jeff-
Ok , got a new prop on the Norma Jean 2
22 C dory cruiser.
It now runs 23 mph wide open and trim tabs down 57k rpm
Trim tabs down brings the nose way down in the front.
My learning curve, never had trim tabs before.
Think I will stick with the Honda 90 for at lease another years
22 C dory cruiser.
It now runs 23 mph wide open and trim tabs down 57k rpm
Trim tabs down brings the nose way down in the front.
My learning curve, never had trim tabs before.
Think I will stick with the Honda 90 for at lease another years
Conan2324":3kvydfft said:
Running with the tabs full down will reduce the top speed. You only put the tabs down far enough to get a decent ride in the chop. On calm water you may not need them much (depends on how your boat is loaded). My tabs are normally about 60% extended when I need them.
Your top speed of 23 at WOT is still a bit low compared to my CD22 with a Honda 90, but maybe you are carrying more weight.