It just started doing it last week.... the gauges all test good.
sender maybe?

btw, it is a soft alarm... beeping, not the solid tone....

Now that's funny!! :lolhit:

Griff is correct, so that most likely leaves the oil reservoir, very similar connections to the wiring for the trim sender and limit switch.

They alarm circuits are all normally open circuits. So if you disconnect the high temp alarm (the big sender on the thermostat housing)the low oil pressure switch (which is the small switch next to the oil pressure sender) and disconnect both wires to the drive bottle you should have no alarm. Replace them one at a time.

Make sure your trim sender and trim limit switch are working for that motor if not then maybe the wiring for the bottle got switched around

in each case mentioned above the alarm wire is tan with blue line and shorting it aout should result in an alarm after 30 secionds to a minute

great info! Thank you very much!! Looks like i got more stuff to check out....

Not bad for an Apache Guy! :party-smiley-004:

Correction the alarm circuit wires are tan and blue

the oil pressure sender is light blue

the water temp is tan

the trim sender is brown/white

very cool, thanks!

this is what I was looking for

http://www.boatfix.com/merc/Servmanl/18/18E4R2.PDF

covers most mercruiser setups

That is outstanding - thank you! Much more detail than my merc manual gets into....

Question: DO you have any kind of schematic that shows how the Mercathode wires in? I dont have anything in my merc manual on it. I have a coupel sicrepencies between the two, and am wonderinf really... whats its main purpose? do I have to have it if it sits on a lift all the time and sits in the water no more than 18-24 hours at a time?

here you go

http://www.offshoreonly.com/forums/g...de-wiring.html