Is it worth up grading

[Conan2324]

I have a 22 ft 2019 with a 90 hp honda.
Is it worth it to upgrade to a new Yamaha 115hp ?
About $10k with trade in.
I would like little more speed up to 20 mph without
giving up too much gas efficiency.
Hoping to have the Norma Jean 5 to 7 more years

[ssobol]

[oldguy83]

Try another prop.

[thataway]

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.

[DayBreak]

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]

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]

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]

Checked the prop is a 13.5 X 15
its a little dinged up , so might try a new prop first.
I usually run 15 mph at 5000 rpms under moderate loads.
Any suggestions on different size prop but I like aluminum is
case I hit stuff on the Mississippi.
Thanks for the help

[ssobol]

[NORO LIM]

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]

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.

[thataway]

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.

[CPlay]

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-

[Conan2324]

I just ordered a new prop, same as the old prop.
The mechanic thought it being banged up was probably the
cause and it only costs $125.
Let's see if it works

[ssobol]