BillR

This year - the last 2 times out, I have had the warning alarms on my motors sound.

1st time out this year; the stb motor alarm would beep very intermittently 1 to 1 1/2 times, then be silenced. Happened about 3 or 4 times.

2nd (last) time out. Ran HARD on the 1st leg of a poker run. After coming off plane this time after a few minutes, both motor alarms sounded and they stayed on for a while!

On the 575's mefi 3 the alarm will sound for:
Low oil pressure
Low Drive oil
engine over heating
low voltage

Each time this happened, I checked all gauges. Everything is fine. Drive oil is fine. Checked every engine sensor connection while alarms were sounding - all fine. (at least I checked the ones I could reach)

This alarm ONLY happens a few minutes AFTER I have come off plane. Turn key off then back on to restart, alarm will resound after a few seconds.
Since all gauges were fine, I came back up on plane, both alarms were silenced about 10 - 15 seconds after throttling up. The alarms came back on next time I came off plane, but eventually silenced after a few minutes. Then ran boat all day (on & off plane) and they never sounded again.

Are there different sensors for gauges and different sensors for ECU?

The only thing different from last year - I removed everything from the motor box and refinished and replaced JUST ABOUT everything in the motor box. Replaced anything slightly questionable.

Any ideas on what could be causing the alarm?

Thanks in advance for all responses.

JaayTeee

There is a oil presure switch that signals the ECU.

It is seperate from the oil sender for the gauge.

The manual refers to them as "discrete switch inputs"

I had a couple of these go bad in my old boat.

Alarm would sound for no apparent reason

It is # 3 in the pic.

http://www.mercruiserparts.com/Show_...er+And+Sensors

BillR

more ideas????

JaayTeee
BTW: where (like exactly where) is the oil pressure switch your refer to and where is it in the manual - I can't find it in there.

Vinny P

I had a similiar issue with an alarm a while back. The problem was a faulty drive lube reservoir switch. It would act up intermittently. I know you said both engines had the alarm go off.. But at least its an idea to look at.

JaayTeee

They make mention of it in the 575 ECM diagnostic manual.

I didn't see any mention of it in the regular 575 service manual.

On mine, there's a tee fitting coming out of the pan rail
portion of the block, just in front of the oil line adapter.

The oil pressure sender points straight down,
the oil pressure switch is on the other port of the fitting,
it is kind of aimed at the knock sensor.

BillR

I have both manuals, I'll look in the diagnostic Manual.

I was afraid that is where it was located. Now I gotta find either someone w/ long arms or someone really skinny. There is no way my fat azz can even attempt to get back there.

It is odd both motors have exactly same issue. I am hoping that since both motors were out and motor builder checked/fixed oil leak from that exact location over the winter - maybe the wires are loose or something. . . . . .

Fanatic

Give me a buzz and I'll give you a hand. Maybe over the weekend.

BillR

What about after 5pm weekdays? Thinking about wed or thurs.

Gonna walk underneath the motor?


Some things never change - right?

Fanatic

Does it have any wingnuts?

Let me see as I work until 5:00 - 5:30 out in Chesapeake. Also, the little woman was in an auto accident and had a partially collapsed lung and so I'm still dealing with that this week...