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BF9.9 props

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tgarnand

New member
Curious if anyone can help me out. My 9.9 will either troll real slow 1 to 1.3 mph or over 3 mph I cannot get it to stay in the 1.8 to 2.8 range it has the standard issue prop now.
What might help so I can run ofc idle a little more but keep it in trolling range ?
 
Hi,

Welcome to the forum.

You ask a really tough question.

Trying to figure that out would either take a lucky guess or a genius at math I think.

I believe the standard prop is a four blade 9 1/4" diameter by 10 pitch.

The pitch....10 inches forward "push" per revolution.... is probably going to have the most bearing on what you want to achieve. So, a lower pitch might get you in the sweet spot you're looking for.

They offer a 9", 8", 7" and 6 1/2" pitch in the
9 1/4" diameter prop and one four blade, 10" diameter with 6 1/2" pitch.

But which one of those should you pick????

That I don't know.

Each one is over $100 so that's what each guess costs.

Hopefully, someone else here can offer you a better answer.

Good luck.
 
Well maybe the prop I have is not standard issue I did buy this motor used ut has the 4 blade 10x6.5. I wonder if the 91/4 x 6 1/2 might be the key ? I went through the same BS with the big motor when new. Thanks for the info it is much appreciated
 
Well, actually, I don't think there is a "standard issue"....I think those are just all the options and they have the original owner pick one. Not sure about that though.

You could try asking the question at an aftermarket prop supplier like Michigan Wheel and see what they say. Might be worth a shot.

Good luck.
 
tgarnand said:
Well maybe the prop I have is not standard issue I did buy this motor used ut has the 4 blade 10x6.5. I wonder if the 91/4 x 6 1/2 might be the key ? I went through the same BS with the big motor when new. Thanks for the info it is much appreciated
Click to expand...
I have a 91/4 X 9 4 blade on my 2014 BF-9.9D pushing a 12’ aluminum boat. I have the same problem as you, too fast for trolling when the fish aren’t actively biting. I turned down my idle a bit and that helped somewhat so I turned the idle down a bit more figuring I’d be golden. Not so, if the idle is too low I ended up with a hard starting issue. Did this last year when the engine was just out of the break in period, over the fishing season last summer I did notice that the idle revs appear to have increased a bit. I’m hoping this year I can get the idle turned down 1/8 to 1/4 of a turn without causing me the hard starting condition. Adding more weight to the boat helped a bit with slowing the boat down, I used my dog (65lbs.) and a 1/2 full sandbag (20lbs)
 
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