383 stoker engine overrev alarm

[Tydeocean]

Hey all,
I have been having a problem with both of my 383 stoker engines. One engine gets to 4500 and the overrev alarm and guardian mode turns on. The other gets to around 5200 and the same thin happens. The gardian mode just keeps the engines at the RPM. I have had this problem for a while and replaced tested some stuff with no solution. I'm back to figuring out what's the issue and was looking for some input or paper work for the reason the over rev alarm is going off. I have a OMC diagnosis tool not the mercruiser one.

 

[alldodge]

Howdy
Have you verified the tach's are accurate?
Checked adjustment on the in gear switch on shift plate?

Have a motor serial number?

 

[Tydeocean]

Howdy
Have you verified the tach's are accurate?
Checked adjustment on the in gear switch on shift plate?

Have a motor serial number?

Sorry it took me so long to get back to you. Some corrections, I'm using a quicksilver DDT not OMC, I the over rev is reading the same RPM on the DDT and the RPM gauge. I have been doing a lot of detailing on the boat before I put her in the water and the other day I needed to drill a hole in the hull to check on how water logged she is and dry a spot up to fix a crack on the starboard stern. She is extremely water logged, foam was soaked and a little puddle when I took out it out of the 4in diameter hole I made, no rot yet though. As far a serial numbers go, only thing I could find was a quicksilver repowered badge so I'm going to need to call them.

 

[alldodge]

Being a reman there wouldn't be one. What year were the motors installed?

Do check the in gear switch, its on the shift plate

 

[Tydeocean]

Being a reman there wouldn't be one. What year were the motors installed?

Do check the in gear switch, its on the shift plate

The motors are a 2005 and are Bravos

 

[alldodge]

Do the motors have 555 or MEFI ECM's?
Where the motors full drop in from Merc installed by a dealer or was it a Merc long block and the MPI system was reused?

If reuse do you know what motors where original?

 

[Tydeocean]

Do the motors have 555 or MEFI ECM's?
Where the motors full drop in from Merc installed by a dealer or was it a Merc long block and the MPI system was reused?

If reuse do you know what motors where original?

Once again sorry about the long response time, busy summer. 555 EMC, not sure about the the MPI system. The stock engine was a 454, but it was to heavy and was cracking the fiberglass supports for the engine. My Grandfather installed the 383's, at the time he was a mechanic and quicksilver dealer, but the push toward fuel injection and the ways the computers worked was not completely clear to him. With that, I took the boat out this weekend and accidentally cavitated for about 15 sec, the engines went up to 5500 and no alarm. I think/hoping the propellers are the wrong pitch, I had to change them anyway so this week/weekend I will be putting them on and testing the RPMs