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Mercruiser 5.0 with Bravo 3 : please help

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businessjett

New member
My boat won’t rev past 4,000 rpm
Just has the 2 fuel pumps replaced
Distributor cap replaced
Serviced in June and spark plugs replaced

Compression tested ok.

I read I should now get the injectors cleaned and look at the exhaust flappers .

Bottom is clean, leg clean, props clean.

Any advice would really be appreciated.

Thank you
Byron
 
I'd check the fuel pressure in the rail and pay attention to the gauge as the RPM is increased with the engine under a load...
 
Thanks for the reply. Good logical advice.
I have a mechanic helping me and we checked that & it was all ok.

I did have dirty fuel, which is why I am thinking the injectors next.

I was wondering if there is a logical order of what to be checking next.
 
I have an update .

Flappers are ok

Next I will have the injectors removed and cleaned after that I am at a loss

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 .
 
businessjett said:
I have an update .
I can get it to 5,000 by trimming the leg right up.
Click to expand...
What seems to be the issue if you can reach 5000 RPM? as that is in correct range while trimming the stern drive up a few degrees while underway by normal design.

What is the year and boat model?
What MPH are you achieving at both 4000 and 5000 RPM?
 
Hello .

It’s a 2004 Sea Ray 260 Da

The issue is it will only do 23mph . Which is at 4000, trimming the leg revs out to 5,000 but speed stays the same.

I have trim tabs and have been adjusting them also .

This is with just myself in the boat
 
A 5.0 EFI is what? 230-260 hp. But not very high on the torque numbers.

The boat is 26 ft long and probably weighs in at 5000 lbs +.

1. Have you ever been able to achieve higher speeds? If so what was the max speed (mph)?

2. As said in prior post, reaching 5000 rpm at WOT with drive trmmed up is exactly where you should be in any boat with a EFI or carbed small block chevy engine regardless of MPH.... MPH is more or less controlled by hull design/size/weight.

My opinion is you are pushing a heavy boat which is way underpowered.

My opinion is, any boat over 22 feet should be powered by a 7.4-8.2 litre (454-502 cubic inch) Big block
Or based on hull design an above normal HP/torque 5.7-6.2 litre (350-383 cubic inch) Small block.

You may be stuck with a great running but slow top speed boat....
 
I have seen many posts where it appears as if the poster came into possession of what I call a "Boat Show Special". This is what I call
a boat that was intentionally built with an undersized engine in order to get a low sticker price.
I have a 23 ft deep V with a 5.7 260 HP. It could use a 6.2...
 
businessjett said:
Hello .

It’s a 2004 Sea Ray 260 Da

The issue is it will only do 23mph . Which is at 4000, trimming the leg revs out to 5,000 but speed stays the same.

I have trim tabs and have been adjusting them also .

This is with just myself in the boat
Click to expand...
With it trimmed up, the prop isn't meeting as much hydrostatic pressure, so it's natural for it to rev higher. Keep looking for the problem if it revved higher when trimmed lower.

How did you end up with dirty fuel- was it water or actual dirt/debris? If debris, I would ask about how you're storing the boat.
 
businessjett said:
Hello .

It’s a 2004 Sea Ray 260 Da

The issue is it will only do 23mph . Which is at 4000, trimming the leg revs out to 5,000 but speed stays the same.

I have trim tabs and have been adjusting them also .

This is with just myself in the boat
Click to expand...
Did it ever do better than this? what prop are you running, is the hull clean? As mentioned 5.0 in a 26 ft boat is asking a lot, so prop pitch has to be very low. May be as simple as dropping 2-4 " in pitch, sometimes folks go up in pitch and think it will gain them speed. Boat just hits the wall power wise ...
 
I have 5.0mpi in my 26foot Maxum 2500scr cabin cruiser. Make sure all inline fuel filters are replaced. Dropping down a prop pitch and upgrading my 3x3prop to a 4x3 Solas prop helped my hole shot and speed and reaching my proper rpm. For a 5.0 mpi is 4600-5000rpm I believe. If you are running a 3x 3 this will help a lot. But might not address your issue if it has been going on for a long time???
 
Maxum 2500 said:
I have 5.0mpi in my 26foot Maxum 2500scr cabin cruiser. Make sure all inline fuel filters are replaced. Dropping down a prop pitch and upgrading my 3x3prop to a 4x3 Solas prop helped my hole shot and speed and reaching my proper rpm. For a 5.0 mpi is 4600-5000rpm I believe. If you are running a 3x 3 this will help a lot. But might not address your issue if it has been going on for a long time???
Click to expand...
He is running a Bravo 3 dual prop. Incase you missed that.

The real answer in my opinion would be to go to a Bravo 2 which uses a much larger diameter prop and would push this under powered heavy boat much better than a Bravo 1 or 3.
Otherwise repower with a Big Block. 454, 496 etc.
 
I agree about the under power for sure.
I also run a Bravo 3, thus my post.

My Maxum is way over 6000 lbs. and was almost impossible to get on plane with more than 4 people on boat.
Going to a 4x3 meant I dont even need to use trim tabs to get on plane now.

When I repower my 2002 Maxum I will likely go to a 5.7 or 6.2 MPI also.
But I am really happy with my boat with the upgraded prop, it made the difference.

When doing plugs and cap, I would do do wires also. No reason to leave something behind when trouble shooting.
Wondering what prop pitch he is running.

My boat is bottom painted and has a large extended swim platform for reference.
 
The original 3x3 props from Mercury are junk compared to newer Hills 4x4 or Solace 4x3.

If you ride a bike up a hill you shift down a gear, same for a 20 year old boat.
Drop a pitch or 2 or more, depending what pitch he is running and RPM he is at to verify prop slip.
 
My questions are:

Who would put a 5.0L in a 26' Sea Ray Sundancer? I don't think I have seen a 5.0L with a Bravo, for that matter.

Is this the OEM engine?
 
My 25.6 foot Maxum came with a 5.0 MPI. with Bravo 3.
I would not be surprised if Sea Ray did it also.

Now EFI is a different beast, which I dont know much about. BUT.
The 5.0 MPI produces 260 Hp, which is similar or the same HP as a 5.7 EFI motor.
If not mistaken.

Would like to know what prop pitch he has, the prop that came with my boat was original, and was not ideal for my heavy boat.
I believe my new prop 4x3 is a 20 pitch, and original was 3x3-22 or 24 ;pitch.???
 
Maxum 2500 said:
My 25.6 foot Maxum came with a 5.0 MPI. with Bravo 3.
I would not be surprised if Sea Ray did it also.

Now EFI is a different beast, which I dont know much about. BUT.
The 5.0 MPI produces 260 Hp, which is similar or the same HP as a 5.7 EFI motor.
If not mistaken.

Would like to know what prop pitch he has, the prop that came with my boat was original, and was not ideal for my heavy boat.
I believe my new prop 4x3 is a 20 pitch, and original was 3x3-22 or 24 ;pitch.???
Click to expand...
HP sells vehicles, torque turns wheels and props- also, injected 5.7L in boats often produce more than 300HP, which started 30 years ago with Mastercraft using the Corvette LT-1. It was followed by Indmar's LTR, which was rated at 330HP.

But the power isn't needed for top speed in most boats, especially yachts- it was used for hole shot when towing skiers.

"There's no replacement for displacement' is accurate- these are normally aspirated, so the power of a 5.0L won't match a larger engine.

Fuel injection isn't really so difficult to understand if it's presented without making it sound like magic. Remove the sensors and ECM, replace the throttle body with a carb and put a regular distributor on it and it's like a typical engine. Specific events are controlled by a few of the sensors, but it's not insanely difficult to grasp the general theories and since most people don't need to know it as deeply as someone who's developing it, servicing injected engines can be done by many who never thought they would ever understand it- some of the people at Mastercraft technical training (including me) were a bit like deer in the headlights at the beginning, but they ended up being good diagnosticians.
 
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