Engine alarm

[JMG]

06 185 Sport, 4.3l Mercruiser TKS. I've been getting an intermittent engine alarm, the beep out of the dash. It occurs at seemingly random times, and with no discernible pattern. A couple of times it was a short beep, a couple of times a little bit longer, today a couple of short beeps followed by a longer one. The only common thread seems to be in higher, above 2900, rpm, or when throttling down from this condition. I have read this alarm has three possible causes, high temp, low gear lube, low oil pressure. I have also read a fourth condition can cause it, low seawater pressure (standard cooling). I changed the oil, replaced the oil sender and sensor, and replaced the thermostat, temp sender and sensor, and drained the lube oil and checked the float in the reservoir bottle, will replace that next (it looked fine, float moved freely, but it may be the sensor has gone bad). If, after replacing lube oil reservoir the alarm persists, what should i check next? Oil pump? Water circulating pump? Electrical connections? Impeller in lower unit has already been replaced,0 in February.
Any advice is appreciated. The boat runs great, but I can't enjoy using the thing if I'm constantly worrying about what might be going wrong.

 

[Lazy Daze]

All of those things you replaced... where they all bad? That starts to get expensive and if you're not comfortable doing some diagnosis, you would be better off letting a shop figure it out - probably a one to two hour job and it would certainly be less expensive in the end to let a pro do it, rather than just replacing things wildly.

But back to your question... first, you do not have a water pressure sensor. The drive lube bottle... just disconnect one of the wires and see if the alarm doesn't come back.

What do the gauges read when the alarm sounds?

If you have a depthfinder, that could be the source, as well.

 

[JMG]

Thanks for the reply. As to replacing things, I don't know the service history of this boat, so it falls under establishing a baseline for maintenance going forward - stuff I had planned on doing this winter anyway.
My depth finder is an add on, so different alarm.
Gauges all read normal, or at least they don't vary widely, so as an index of sorts I take it to mean things are as they should be.
As I said, very intermittent, ghost in the machine situation. I did read on the iBoats forum that the sensor wires are connected, in some part, for some reason, to the ignition module and that connection can become loose causing symptoms like mine. I'll check that next.
And good to know about the water pressure sensor absence. Thanks.

 

[Lazy Daze]

If you're sure it's not the depthfinder alarm - meaning the noise you hear is definitely different than initial alarm you hear when you turn the key on... and it's not the reservoir bottle... yes, the next most likely thing is a loose connection somewhere. Especially since the alarm sounds like it is a bit wacky. The good thing is that it's a small boat and a pretty simple system - meaning it's on the easier side of electrical diagnosis.

 

[JMG]

So, I was out today, same intermittent beep, and I disconnected the temperature sensor lead, and the alarm stayed silent the rest of the day. I think I have isolated the problem to the temperature sensor and/or the wire lead running from it. As the sensor is a month old, although it wouldn't be unheard of for it to be faulty out of the box, I'm thinking that the problem might be in the connector that attaches to the sensor, or the wire from the connector, although it would be much easier to just replace the sensor again. How do I check whether the sensor is good or not? Also, there are two threaded openings on that side (port) of the thermostat housing, one for the sensor (aft) and the other fitted with a bolt for a plug (forward). As both openings go to the same space inside the housing, can the position of the plug and sensor be swapped? I believe the threads match, if I remember correctly. When i removed, cleaned, and replaced the elements within the housing, I put things back the way they were. The aft opening is directly under a couple of hoses and right next to the drive lube reservoir tube, and it kind of puts the wires from the sensor in a bind.

 

[Scott1523]

So I have the same problem with a 2011 185 sport. Only get the alarm over 3000 rpm's. It's very sporadic and the strange thing is, it only happens in the beginning of the season. Usually by July it stops completely. Where is the temperature sensor? Sounds like that's my gremlin. Next time out I am gonna try the lube sensor since it's easy.

 

[Jeff Delbuono]

Here is the alarm, code chart

 

[Jeff Delbuono]

Also good advise, get a temp lazer gun. Guages are sometimes wacky. You can get a better read with remp gun, i point at thermostat housing and risers. Temp sensor is normaly in the thermostat housing. 1 is for guage and 1 is for alarm