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Discussion Starter · #1 ·
I have a friend that just got a 23' Larson BR boat. When he runs it at WOT the rpm goes 5400 to 5500 rpm with his 2 kids , wife and him with a full tank of fuel. The motor is a 5.0 merc 280hp.It has a 3 blade 19 pitch aluminum on it now. What prop/size should it have on it? or where should the rpm be for that motor? is 5400 or 5500 rpm right for that motor?
 

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I have no idea... I've never seen a mercury 5.0 280 hp engine, but his #'s sound impressive with that kinda of weight, how fast is he getting??
 

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Should be 4600-5000 RPM's I would try a stainless 23P if his tach is accurate. The most powerful 5.0 Mercury put out was 260HP.
 

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Discussion Starter · #4 ·
Mkos1980 said:
The most powerful 5.0 Mercury put out was 260HP.
That could be it. I was not sure :D
 

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Discussion Starter · #5 ·
Fyhr Factor said:
I have no idea... I've never seen a mercury 5.0 280 hp engine, but his #'s sound impressive with that kinda of weight, how fast is he getting??
He said it was doing 50 mph gps. I was not there so I can only tell you what he told me.
 

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Very good performance from a 5.0 in a 23ft boat. I'd love to turn those rpms's with a 19 in my boat. Means theres alot left in prop changes. I was doing 53 at 4400 RPM with a 21 when it was the stock 270hp 350 Mag.
 

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Discussion Starter · #8 ·
RSCHAP1 said:
The 5.0 260 Mercs sound impressive.
Thats what I told him. :rolleyes: But I just had to ask so I could help him out.
 

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Discussion Starter · #11 ·
SINGLE SCREW 32 said:
Hey Doug, you been getting out lately?
Little bit, I will be out Friday morning 2 head 2 the inn. :)
 

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Yea i hear ya.as long as the grass keeps growing i'll be out as wellheading to the beach this weekend but hope to be out all 3days on the 4th. Hope to catch up to ya soon.SS32
 

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Discussion Starter · #13 ·
I want to try to catch up with you at Lloyd's one day.
 

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might be worth checking the tach....

In factory trim, that engine should be running out of cam around 5000... and should be well past peak hp at 5500...
 

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and the 260hp/305 is efi and computer controlled so Im pretty sure it has a rev limiter as well. Could be wrong though..
 
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