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scyharris
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Need prop advice

Post by scyharris » 12 May 2011, 17:11

Hey guys,

Got the motor on the 16' Bass Tracker. It has a 70 hp Johnson 2 stroke. Last night it ran 39 mph per gps. Current set up is a 13x17. Do you think a 19 or 21 would make any difference. Also, I am running a Bob's Machine Stabilizer plate and a 4" jackplate. Thanks in advance. BTW, I do not have a tach so no idea of the RPM's.

Scott

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redbug
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Need prop advice

Post by redbug » 12 May 2011, 17:26

what are your rpm's running at wot? if you are hitting the rev limiter then you can go up in size
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scyharris
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Need prop advice

Post by scyharris » 12 May 2011, 17:39

Do not have tach, so no idea of rpm's. Sound like it is spooled up pretty good though. Do you think 19 or 21???

Thanks

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redbug
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Post by redbug » 12 May 2011, 17:52

i couldnt venture a guess without the proper info
i'm sure someone will take a shot in the dark for you
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crazymanme2
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Post by crazymanme2 » 12 May 2011, 21:25

Every pitch change you'll lose about 200 RPM.I'm running an 85hp with a 21 pitch at 5700 rpm's & when I went to a 23 pitch it was too much.If your boat isn't heavy you might be able to spin that 19. [-o<
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Skidz
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Post by Skidz » 12 May 2011, 23:02

To get any really good idea of what you need in a prop, knowing your RPMs is a must. Tinytach makes a good and it's only about 40 bucks.

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Pappy
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Post by Pappy » 13 May 2011, 08:31

I think you are propped about right but am wondering if you are getting all you can from that set up. I have a 15' Whaler with a 3-cyl 60hp on it running 41mph at 6050RPM with a 4 blade 17" on it. The boat will run a 19" 3 blade but is sluggish coming out of the hole. No jack plate on mine. With the cavitation plate exactly parallel with the bottom how high is your plate above the bottom? Why are you running a whale tale on this set up, have run plenty of similar set ups like yours and haven't seen the need for one. You do have trim on the engine, right?

scyharris
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Post by scyharris » 13 May 2011, 11:47

Pappy, a whaler hull is drastically different than a flatbottom. The stabilizer plate is mainly to help with sliding in turns. However, it does help keep water around the prop. It does have trim and tilt, and I believe I can get more out of her with a little tuning. Main reason I am asking about prop is because this is the one that came with motor. Cav plate is 1 inch above keel with no slippage. BTW, the motor came off of a 15 whaler. He only saw 37 max. Thanks again.

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