2500 RPMs at WOT

Eddie B

Member
Jun 21, 2021
61
Stamford CT
Boat Info
2003 Sea Ray Sundancer 240
Engines
Mercury 5.0 MPI
Hi everyone. So my 2003 240DA with 5.0MPI went in the water yesterday. She started up and idled fine. Cruised smooth through no wake. But when I opened her up she hit 2500 and would go no further. Right at 2500. Did not seem to bog. Didn’t stutter. Just would not go to higher RPM. No alarm.
Risers and manifolds and elbows were replaced this winter. Tuned up and oil changed in the fall, ran perfect last day of the year on the way to winter storage. Marina that did the manifold work it is checking things out. They are starting with the timing. I have read threads about timing, fuel, compression, exhaust flapper and so on. My head is spinning and my wallet is empty.
 
Start with the simplest things first.
1. How old is the fuel, was storage additive used when put away.
2. Check/change fuel filters
3. Check fuel rail pressure
 
I would check fuel pressure. However, I had the same issue and my distributor cap was loose. Would not plane out with several people on it.
 
If I'm understanding you correctly, the RPM's stopped dead-on at 2500 even though you were able to physically advance the throttle further? Assuming that...

I believe you have a Smartcraft engine but you DO NOT have Smartcraft gauges, right? My first guess is that a sensor wire was not reconnected or possibly sheared off during the service work. Typically this activates the buzzer, but it could be an error/communication issue within that system or maybe the buzzer doesn't work (do you hear it at startup?).

Also, check all of the spark plug wires to make sure they're going to the right plug and fully seated at both ends.
 
Thanks everyone. So she was stored full and I added stabil marine. I have not checked the fuel filter or pressure but I will in the next day or so. There was an issue at initial season startup with the distributer and the plug wiring but the mechanic sorted that. one of the plug wires was off or loose so now I know what a misfire sounds like.

lazy, you are correct all around. Dead on 2500 which is why I thought it might need a computer reading. I did replace the outdrive trim lines, manifold and rams. And the Mercathode on the gimble housing because you kinda have to and the one that was there was toasted. I am wondering if that connection is not great.

my alarm does chirp at startup and I had issues with my shift position sensor last year and that thing would not shut up. So I know it works ;-) but no alarm. Seems odd that guardian would kick in but no alarm.

marina mechanic said they would check the timing but she ran smooth even at 2500. No bogging no fluctuation for 2-3mins at 2500.
 
The Mercathode won't put the engine into Guardian.

Weird that you didn't hear an alarm. BUT... maybe being a non-SC equipped dash, it doesn't sound the alarm... except for the "normal" things (overheat, low oil pressure, drive lube bottle low).

The problem definitely sounds electrical in nature.
 
Well, heard back from my marina. Apparently two of the plug wires were swapped when they did the manifold work. The problem solved and I am great full it was not something more significant. Amazing that with two wires switched it ran so smooth and hit a precise rpm. She’s back in her home slip now and and ready for the season (she just needs a good wash and wax). Thank everyone for the info.
 

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