Merc 496 HO losing RPM
 

2003 Baja Outlaw
twin 496 HO's
Boat ran great all day.....temp were perfect, oil psi good, volts good.
Then trying to get on plane, stb motor would get to 4000rpms, alarm would go off and rpms would drop steady back to 1000. During this gauge read outs were normal.
Has anyone had a simmular problem ?
Thank you
Bart A

Yes could be a number of issues. You will need to scan pcm.

Thank you
planning to set that up for next week
purchasing scan tool
putting in the eng info....
Rinda Scanners
Tech mate Pro 94706. ?

if you need the correct scan tool and the correct adaptor let me know I can direct you.

Scan tool
 

Yes please
boat is a 2003 Baja
Twin 496 HO
let me know what other info you may need
Bart

great I can direct you where to and what is needed -- only thing needed your contact info. Thanks.

Scan tool
 

Bart
734 578 2815

As some said a scan will be needed. That said I had the same issue and the scanner was showing all ok.

it wasn't until we chose to single out and watch the water PSI that we found a bad pressure switch that would stop reading water PSI at speed and was causing the issue. Cheap part, long and drawn out testing to repair.

Baja
 

Thanks Nate
is it the sensor in the water pump housing ?

Baja
 

I was also told my temp readings are too cool !
I find that hard to believe.
Last season I was running 185 to 190+
I pulled heat exchangers and many were blocked.
Cleaned out all tubes....dropped temps to around 170.
Over the winter I rebuilt the Hayden water pumps, new wear plates and impellers.
Temps now 160-170
B