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First shake down run

jrat

Member
"Hello all,

This weekend I


"Hello all,

This weekend I took my Bayliner out for a shake down run. Everything went great. Temp stayed at 180, boat planed with 5 adults, 3 children and 2 dogs and a full cooler. The only thing I have a problem with is, at WOT, I'm only getting to about 4400 RPM. The crusing speed of the motor is 4900. The throttle on the carp is wide open. Do you think I'm over proped? Ho can I get the missing 500 RPM? Or should I leave it alone. My top speed is around 35 MPH. I'm not to sure the gauge is accurate."
 
"I see two ways to increase yo

"I see two ways to increase your RPM: leave 4 adults ashore, or get a propeller with less pitch."
 
"Hard to say if you're ove

"Hard to say if you're overpropped if you don't tell us what prop you have on it. You didn't say which motor and drive you have, either."
 
"Sorry about that,

AQ125B


"Sorry about that,

AQ125B (120 HP)/ 270D

The prop only has (R) and (Michigan) stamped on it so I cannot tell you the pitch or diameter.

I will remove the prop and see if its stamped on the inside. El, It will not rev over 4500 with just me in the boat and no gear. So its not a weight issue. Could it be the accelerator pump adjustment? I have the air/fuel adjusted properly. Again, this isn't that big of deal, I'm still getting alot of power but would love that extra few RPMs."
 
"I don't think it has anyt

"I don't think it has anything to do with the accelerator pump. If the pump was defective, your engine would react more slowly to a throttle increase, but eventually it would reach the top RPM. If your current prop is in good condition (no bent blades, etc) and your carb is in good condition, my guess is that you need a prop with one or two inches less pitch."
 
Post the part number of the pr

Post the part number of the prop- I have a catalog with Michigan props and I can look it up.
 
"Thanks Jim, But I think I got

"Thanks Jim, But I think I got it, The PN# is 082032, Thats a 3 blade, 14 diameter, 19 pitch. Remember, I have a AQ125B, 120 HP running @ 4500 at WOT. Max RPM is 4900. How many RPM is achieved in every drop in pitch? Thats the question!!! Thanks for all the help guys!"
 
2 inches decrease in pitch sho

2 inches decrease in pitch should make you win 300-400 RPM. You may want to try a 14 x 17.
 
Could you borrow a used one to

Could you borrow a used one to try it first? You may be able to get one on a loan basis from a propeller shop or from a Volvo dealer.
 
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