Mercruiser won’t rev over 4,000

[businessjett]

I have a 2004 sea ray 260da with Mercruiser 5.0 and bravo 3 leg



I can’t get it over 4,000rp and 23mph



I can get it to 5,000 by trimming the leg right up.



Fuel pumps ok



Fuel psi ok



Flappers ok



Distributer cap ok



Fuel ok



Compression ok



Temp ok



Bottom clean, leg & prop clean



New spark plugs



No beeping or fault codes on smart craft



No fault codes on diagnostic device



Serviced June 2023



Oil levels good



Throttle cable checked



Props checked for damage



No idea what to do next . Any suggested would be appreciated .

 

[Bill Curtis]

Always been like this or just started?
Always been this way, then under powered or over propped? Lot of boat for a 5.0

 

[dwna1a]

Uneven loading of the boat (weight). As Bill said, prop. or just underpowered

 

[Yendor]

Both observations preceding this post are good ones. The question(s) then become:
What does the speed do as you trim up, on your way to 5000 rpm? Presumably it decreases.
Are you running on a plane at 23 mph? Is it settling back into the water when you go past 4000 rpm?
How may many inch pitch props are you running?

When I was sea trialing Sundancers (240s-290s) the 5 liters seemed under powered for my liking. However, your quoted 23 mph sounds pretty low to me. Cruise speed maybe, WOT don't sound right.

That is a BIG boat for a small block. Doesn't seem likely that Sea Ray would deliver a boat that didn't do better than that; somewhere along the way someone must have changed the engine or the props OR your engine is not as healthy as you presume it to be.

Which brings us back to the beginning (of this post), and what size props are you running?

 

[Golfman25]

What do you mean be trimming it up? Sounds like you‘re not trimmed properly.