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Prop for trolling

ssmith1347

New member
"I have a 9.8 Tohatsu Fourstro

"I have a 9.8 Tohatsu Fourstroke motor on a 19 foot Alumacraft. When trolling at idle it shakes and doesn't run smooth, and the speed is 1.5 to 1.7 mph in smooth water. Sometimes I would like to troll slower than that. Is there a prop that would push less with more rpm? I currently have a 7.5 prop."
 
"The lower in pitch, the slowe

"The lower in pitch, the slower the boat will move and the higher the engine RPM will get. Dropping down to a 6.5 pitch might help a little."
 
"I found 2 5 pitch props on In

"I found 2 5 pitch props on Internet outboards.
3B2W645110M 4 blade prop
3B2W645125M 3 blade prop
These are not listed in my parts book, but they are listed for 8 to 9.8 hp motors. Will these work or not? I don't want to damage my motor."
 
"Of course they will work, oth

"Of course they will work, otherwise we wouldn't have them on our website
Propeller selection is done by trial and error to determine the best possible propeller for any particular application on any particular day. IE More than one will work, but usually one will work better on that day. Having said all of that, the 4 blade would be a mistake and the 5125 is PROBABLY too low. I suggest a modest change to the 6.5 pitch rather than a huge change to a 5 pitch. But, it's your call."
 
"I have this same "issue&#

"I have this same "issue", WHich really isn't an issue... anyway. I am going to get an 6.5 pitch for my 8 Tohatsu and see if this helps my motor to run smoother on long trolling sessions. BTW right now it's a 7.5 pitch"
 
"I have a heavy 18.5 foot boat

"I have a heavy 18.5 foot boat, tried the 7.5 down from the std 8.9 and whilst it def helped I think the 6.5 will be the best compromise.

I still want some bite low down as use this for trolling etc, so don't really want to be running at high rpms but I did want to be close ish to the lower WOT range"
 
Drop down to the 6.5 pitch pro

Drop down to the 6.5 pitch prop but stay off full throttle hopefully the shift to higher rev range at same given speed is enough to smooth out the running charactoristics of this engine

But ultimatly its like T\Guru says its trial and error
 
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