need help choosing prop for 9.9 johnson

[northmansx]

Looking for a little advice in choosing a new prop for my 9.9 johnson(2003). Currently i run a 9 1/2 x 10 that may have a little shaved off from grinding rocks in a low river. I am looking for more thrust to help push a heavy load such as 2 hunters, some moose meat and our gear. We use 14' boats and would like to get more speed or thrust out of our motor while loaded. Any suggestions would be great. thanks

 

[steelespike]

You should read the stickys at the top of the page.
To do this right we need your wot rpm and speed lightly loaded.
Does the boat plane with a load? Some moose meat"??Is a little vague.
Not knowing the details assuming a 2 stroke I would guess a 9"pitch 4 blade something like the Solas Amita listed here at Iboats. 2113-093-09.
You should have a tach. A Tinytach will do. And a GPS for speed.
You may be able to raise the motor on the transom.Antivent plate about even with the bottom.Might help hole shot and speed slightly and add a little bottom clearance.
You might have to raise the transom to gain full height.
A bare bones 16 or 18 footer might plane easier with a load.

 

[northmansx]

Re: need help choosing prop for 9.9 johnson

Thanks,

I realize it's not all the info that would help out the best but my boat and motor is at a remote fly in camp and i have not used a tach to get the rpm. Some moose meat means about 700lbs, 2 guys about 400lbs and 100lbs of gear and fuel. perhaps it's a heavy load and no prop will help out that much and i should find a 15 or 20 hp if i want more push.

 

[elkhunter338]

Re: need help choosing prop for 9.9 johnson

I have a 9.25x9 solas 4 blade on my 15hp 2 stroke johnson with a tiny tack.
14' klamath with 1 person at about 4,000 feet in elevation tach at about 5.2k
3 people tack at about 4.8k
On a 21 boat as kicker at sea level tach at 4.6k
I would go with the 7 pitch on a 9.9.
I saw good performance change with heavy loads in my 14' boat, but lost top end speed with one person.
At sea level you can over rev the engine with 1 person.
I am glad I bought the prop.
I should have probably got the 10x7 and they offer a 10x5.

 

[steelespike]

Re: need help choosing prop for 9.9 johnson

Unless that is a very large 14 your probably at least 300 to 400 lbs over the rating.
Don't forget 115 lbs for the motor.It is highly unlikely the boat will plane with 1300 lbs aboard.
our old 15 ft utility with a Gale 25 would struggle to plane with 4 adults aboard
When we got an 18 same motor planed easily with 6 adults.
If there is any way to get a 16 or 18 ft utility up there I think you could double your speed
with a 25 not so on a 14.Our 6 person load probably 1200lbs would run about 18-20 mph.
The 18 footer weighs about 375 dry.
As it stands elkhunters suggestion of a 7" pitch is probably about right.
Will over rev severely with one aboard.Loaded it will at least put the motor closer to its rated rpm.Much better for its long term health.

 

[northmansx]

Re: need help choosing prop for 9.9 johnson

thanks for the ideas guys. appreciate the help.

 

[Mi duckdown]

Re: need help choosing prop for 9.9 johnson

check your free board. Good luck hunting.