Engine alarm

[Westwind]

This was my first cruise with my new boat. Ran for about 45 minutes then the engine alarm went off. We're talking about a 1995 SeaRay Sundancer, 5.7 Mercruiser EFI. I checked the oil levels as per the manual and they are o.k.. The temp at the time (and for most of the run) was around 170. I took it easy on the way back in (about 15 minutes more). Any thoughts? I'm a newbie to boating so please respond with that in mind. Thanks!

 

[vinney]

Re: Engine alarm

Did you check the gear lube sterndrive reservoir. If the boat was prep and the reservoir wasn't full. The drive will run and burp some air out and bring the level down in the reservoir. There is a float in the gear lube reservoir that will sound an alarm when gearlube is low in the reservoir.

 

[Westwind]

Re: Engine alarm

Yep, checked that too and it was fine. Any other ideas? Thanks.

 

[Boatin Bob]

Re: Engine alarm

It almost sounds like a false alarm, I think you have 3 sensors for the alarm, high temp, low oil pressure and low gearcase lube, anyone of the 3 could set the alrm off, you will have to go through one by one and eliminate them. The high temp and low oil pressure should be single wires on the switch so you pull them off one at a time, the gearcase lube resevoir has 2 wires in a plug I think. I think these are tan with blue wires.

 

[Westwind]

Re: Engine alarm

Is it possible something happened to cause a drop in oil pressure? Bad oil pump? I did check the oil after the run and it was fine but maybe something caused the pressure to drop? <br /><br />Are false alarms known to occur? As this was my first time out I am a bit concerned. Thanks again.

 

[vinney]

Re: Engine alarm

Agree with the false alarm. Three sensors only. Need to remove one at atime to find false alarm. Oil pumps don't go bad on small blocks.

 

[Boatin Bob]

Re: Engine alarm

You have to be down to almost zero oil pressure for this switch to sound the alarm, I assume you also have an oil pressure gauge, was it reading correctly? The way that alarm works is it has 12v going to it when you turn on the key, anyone of the 3 switches can provide the ground in order to make it sound, those switches provide the ground when closed, the high temp one should never close unless you've got some serious over heating, the low lube shouldn't close unless you are low on lube, the oil pressure is closed all the time when the engine isn't running, thats why when you first turn the key on the alarm goes until enough oil pressue builds up to open the switch (couple of seconds after starting) Just go through them 1 at a time, a manual with a wiring diagram in it would help you a lot.

 

[Westwind]

Re: Engine alarm

Hey guys, thanks for all the help. To diagnose this as you describe doesn't the alarm have to be going off? According to the manual, the alarm turns itself off after two minutes, which is what it did. Anyone familiar with how it resets itself? Does turning the ignition off do it? I ran the boat for about 15 minutes after the alarm shut off and it didn't come back on. However, I did ease up on her a bit. Thanks again!

 

[Boatin Bob]

Re: Engine alarm

Sorry...I thought it was going off all the time, have you started it again since then? I guess you have to wait for it to do it again and pull the wires off at that time. Not sure how it resets itself unless there is a timer built into the alarm itself.

 

[Westwind]

Re: Engine alarm

Started it just for a minute or so. Was afraid to let it run for too long not knowing if something was wrong.

 

[Westwind]

Re: Engine alarm

Update- Had the boat out today and the alarm went off again. Happened about 45 minutes into the run again. This time the oil pressure gauge read zero. Immediately shut the engine and checked the oil. It was fine. Started the boat back up and the pressure was good. Is it possible the alarm is wired through the same oil pressure switch that leads to the gauge? If so, perhaps the switch is bad?

 

[rodbolt]

Re: Engine alarm

hello<br /> the system uses two seperate devices to monitor oil pressure. a discrete switch for low pressure alarms and a variable resistor sensor for the gauge. sounds like a pressure problem. odds of both failing at the same time are slim. pumps do go bad but not often. check the oil filter bypass valve for debris.normal pump failure is to much pressure from a stuck relief valve. however I have seen a few that the relief valve spring failed. other than that the pump is a positive displacement gear type pump and they just rarely fail.<br /> good luck and keep posting

 

[Westwind]

Re: Engine alarm

Update- Had a certified Mercruiser mechanic check it out this week. After running a diagnostic test he said the thermostat was not working properly and was concerned that the oil, which was recently changed by the place from which I bought the boat, may have been the wrong viscosity. He changed the oil and replaced the thermostat. Diagnostics looked good at that point. I had her out for good half day of running today and the alarm did not sound! A good sign!