Do you know the OEM Prop size for a 05 Bayliner 265 with 5.0NA 220hp Carb engine.

DKVNY

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Oct 9, 2011
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5
(a little back story feel free to skip 1st paragraph)

1 owner (Father in-law), unknown maintenance history other than winterizing yearly. I had the boat yanked Sunday after being out and not happy with performance (explained later). I just had the motor yanked by my buddy to check out and be sure everything was on the up and up...it Dynos at the 232hp Compressions are pinpoint correct and I had the entire Alpha 1G2 Leg taken apart incase there was something slipping (they say it looks brand new no signs of wear not even any discoloration where they usually start turning a little blue from heat). Boat lives on a lift and so not painted on the bottom...also not used a lot at speed (80% at 6mph) so no cupping or other wear on the bottom I'm trying to get this back to 95% so we can do a Ashes ceremony at his favorite places come July...so it's more than important to spend all the money to get this right for the family.

(what you need to know)
I know there are about 45k different factors on what the correct prop would be for my situation but I'm going to give everything I can to help out. I have looked online since taking owner ship and cannot find a OEM # or dimensions anywhere....I have all the original paperwork and still can't find a damn thing....

I just inherited this 2005 Bayliner 265 with the Mercruiser 5.0 NA Alpha1G2 out drive from my inlaws and I know some thing is wrong with the prop...its a new 15.25x15 to replace what was on there (but looked like it had a couple rounds with Tyson at his prime) Aluminum 3 Blade....took 2:17seconds to get on plane last weekend with 10 knots head wind and 1:45 down wind. (bimini top over front of cockpit was up so I know that was a nice air brake) top speed up wind was 24MPH 3400 RPM (WOT) and down wind was 28 36-3800RPM (WOT)...WOT is supposed to be 44-4800RPM.

Boat is Bayliner 265 (27') Weights in loaded as loaded at about 6800 (on a scale when pulled) with fuel, water and gear adding people I guess about 7500 max...Knowing I was going heavy the gear weight was mostly up front down stairs and people were in cockpit to spread it out as I could.

Everything I see says 14.75/16 x 13-17P is the correct prop...but knowing that I should gain 150-200 RPM per inch of Pitch Drop (from my 15 I have on it) It looks like I should be running a 10" Pitch with this math....so Yeah...

Anyone know what it originally may have come with...I'm looking for a baseline to continue calc's from to see where I should try next rather than buying one of everything and spending all the inheritance this year alone on propellers.

Thanks in advance.

Dan
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,306
first, check your tach

second, check your fuel system bet you are running out of fuel at the top end causing your low WOT

third, you cant go from the 15 pitch prop you have to a 17 pitch and gain speed.
 

QBhoy

Fleet Admiral
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Mar 10, 2016
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8,286
Guessing game usually, but I’d say around a 17” wouldn’t be far off.
but what I do know, is that a couple of similar boats I know of, run a big 16x16 black max well, apparently. Never actually been on them running wot to see if it’s suited...but the owners seem happy. One is a ‘96 2655 with 5.0 carb. The other was a searay 240 with 5.0 carb. Both alpha
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,306
I would say 15x15P based on the performance of the same motor in my searay and that was 3600# and used a 15x19P
 
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