Monterey 275 SY

blazschmidt

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Aug 7, 2023
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4
Hello,

I purchased used Monterey 275 SY with Mercruiser 350 Mag and Bravo 3 outdrive. Boat had installed 24p props. I had a lot of problems getting on plane. When I was fully loaded it was impossible to get on plane (engine compression was checked and everything is perfect).

Because of this problem we installed 21p props - which my technician had on stock. Boat now planes very fast. I run it between 3600-3800 RPM around 22NM. WOT is 5000 RPM.
When I did my research on boat history I saw that previous owner who had boat from first day didn't even plane an run the boat around 1500-2000RPM.

I am interested if 22.5 props (or any other) would be better to get faster speed and better fuel consumption which is very important topic these days:)

Do anybody know which props comes with this boat?

Fuel economy right now is around 45-50 L/hour or 2.2-2.4 L/NM.

Thank you for your help.

Best regards,
 

alldodge

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Mar 8, 2009
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42,540
Welcome
What year is the boat?
Better yet what is the motor serial number?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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50,233
I would run the props you have. That motor will spin 5000rpm all day
 

blazschmidt

Recruit
Joined
Aug 7, 2023
Messages
4
Hello,

Boat was build in 2009, engine serial number is 1A345248. Gear ratio in outrdrive is 2.20:1

Best regards,
 

alldodge

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Mar 8, 2009
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At 3800 rpm your slip is 27%, not great but typical for a heavy cruiser

S/N shows as Scott mentioned 5000 is max WOT and should have no issues turning it
If slip is decreased so will max WOT
 

blazschmidt

Recruit
Joined
Aug 7, 2023
Messages
4
Hello,

Thank you for your answer. So you recommend I stay with this props?

With 24p props I got 4100RPM WOT only.

Best regards.
 

alldodge

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Mar 8, 2009
Messages
42,540
I would say if you normally run heavy (friends onboard) then stick with the props

If friends don't come often and your ok with being able to take off a little slower, then the 22's will drop WOT to around 4800.

Cruising at 3800 or 3600 will not change the fuel burn and the motor has no issue running high because it's not working as hard
 
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