Expensive Date

Constant no beeps, cleaned battery connections and tested both battery's.Checked all the connections I could find. Will either hook up to scanner again during launch or unplug drive bottle if it does it.

GO4BROKE

I would put crank sensors in both engines.

Expensive Date

Probably will, but want to fix this "ghost alarm" first.

BUP

Since you came back up and made it clear about the constant warning horn but you did not make it clear about your codes. PRT EMCT and the STB EMCT.

They should report if they are PRT EMCT CKT LO or STB EMCT CKT HI or most likely this is what you really have as an ACTIVE FAULT for your constant alarm is STB EMCT OVRHT and PRT EMCT OVRHT.

If this is an active fault they mean Starboard exhaust manifold temp high and Port exhaust manifold temp high. Cooling problem and or that damn sensor problem in your exhaust maniflolds. This will cause a constant alarm when there is an active fault plus showing up on the scan tool. Do you have smartcraft - if so these codes will show on the smartcraft gauge as well. The fault message #'s are 179 for STB EMCT OVRHT and 160 for PRT EMCT OVRHT.

Today I tested the drive lube bottle alarm for a ECM 555 - 5.0 MPI Mercruiser it was a intermittent continuous horn not a constant one. A different app than yours but again according to Mercruiser even on the 496 its the same not a constant horn but an intermittent one for the drive lube bottle. I still think 1 of the 496 models has a constant horn as well for the gear lube bottle but can not remember which one. Maybe it is certain year(s) / serial # break.

Couginitnordic

Only a theory but I thought my alarm was going off when I launched too. It is actually my depth sounder going off. The alarm is set to go off when It is less than 3.5' of water. It goes off sometimes when it loses it's reading as well. Just a theory.

s022mag

Not to get off topic but is it normal to here a few beeps after you start the motors. I get a few when I turn the key but after they start there is a tone for about a second?

jbraun2828

Water pressure sensor will give a constant alarm with no beeps and will put motor into guardian. Sensor could be bad.

BUP

it would be wise first and foremost to rescan the motor and see active fault codes currently - fix them and then see how things are with the motor. just throwing parts at it a lot of times is wasting money and time.

he reported but not sure about current fault codes or if these were current active faults - the STB & PRT EMCT showed up as faults. IMO I think they are active so that would be the first place I would start plus these faults again they are showing on the his scan will set off a constant warning horn.. It totally makes no sense to start anywhere else, Rescan the motor clear all the fault codes first. If it is an active fault it will show back up. Good luck

Expensive Date

I have not been able to do anything with work. Planing on launching at friends marina Sunday with a scan tool hooked up. Manfolid temp switches new. Will advise

Expensive Date

Ok, finally got a chance to launch with a scan tool hooked up. I always just idle engines at ramp and the 1/3 mile to channel. Turns out it is taking the one engine with the alarm a little longer to pull up enough water and keep the manifold temp sensors happy. Pump does have a little wear on the plate but I have used worse, if RPM is bumped up to 1200-1500 for 30 seconds after initial start it seems fine. Water pressure is ok running just initial prime after boat is on the trailer all week.Will try again Sunday and probably just order the Hardin Marine pumps. Will advise and thanks for all the help.