Alarm beeping and wailing solid.

MOKGANDHI

2004 Rinker 270 Fiesta Vee, 350 Mercuiser Mag MPI, Bravo III. Getting a double beep from the alarm at low RPM's, a solid wail at higher RPM's/on plane. I believe that the only sensors connected to the alarm are overheating, low oil pressure, and low outdrive reserve tank level. Engine was running cold due to thermostat being held open by small rocks. Replaced t/stat and engine now runs at 160 degrees. Had my gimble bearing, bellows, and fluid changed out in the outdrive over the winter, reservoir is full. Oil pressure was on the low side and smelled of gasoline, but oil pressure was above the minimums. Changed oil and filter, fuel filter/water separator, cap, rotor, wires and plugs. The alarm still beeps twice at low RPM's approximately every minute or two, only now it's intermittently. First trip on plane it only did the dual beeps. Second time on plane it was the solid wailing, again. I was thinking the oil pressure sensor for the alarm is bad as the gauge reads the correct oil pressure and fluctuates with engine RPM's. I don't want to start throwing parts at this as that sensor alone is approximately $75. Any ideas, similar experiences? Does anyone know of a reputable mechanic, that does sidework, would come to my boat, and is located in the Harrison Township area of Michigan? Any and all ideas would be greatly appreciated as this alarm is very annoying and we have lots of long distance plans for our boat this summer. Thank you in advance.

mvn

I could be very wrong but a quick read of the PCM 555 manual shows numerous warning causes.  For example, low seawater pressure at idle results in two beeps; at higher rpm's a continuous warning.

Is the engine derating (less power) itself at higher RPM?

I'm sure there will be someone along soon with some better advice.  Hang in there.

Mark 

Babyboomer

MERCRUISER HORN WARNING SYSTEMS

http://media.channelblade.com/EProWebsiteMedia/3506/Mercruiser%20warning%20horns.pdf

Babyboomer

On this link there is a Code Reader for $49. has anyone ever used one and are the worth the money

CodeMate - MEFI Code Reader

http://www.rinda.com/acro/prodlist.pdf

Dream_Inn

I've used the Mer scan tool several times (dockmate has one).  Works very well.  I went with the smartcraft vessel view for a bit more though and got everything on display live.  Well worth it for any do it yourselfer or for alarms or even just the fuel flow.

MOKGANDHI

Thank you everyone. Looks like I will be purchasing the code reader.

TikiHut2

Based on MVNs code guess could it be a "partially" blocked raw water intake or nearly dead impeller or would the engine temp probably rise too. 

I'd be curious about the price on a reasonable reader too but at $400+ they look a bit pricey for a semi-casual gearhead, but otherwise it'd be great especially if it'd give me current engine hours since my old Faria tach/hr meter gave out.

DIs Smartcraft gauge is a sweet upgrade that'd solve both.