Engine Warning Buzzer???

[jefndeb]

I just finished removing/cleaning and reinstalling the sea water heat exchanger on my Yanmar 6LY-2AN-STP....all went well but the warning tone does not go off after the engine is started.....I cant find anywhere in the Mainship manual what this tone is for...low oil pressure, over temp, no water flow???

I am thinking its something to do with fresh water level (coolant) but cannot find any reference for it anywhere...there is no idiot light associated with this tone telling what this warning is..

Any suggestions??

 

[boatpoker]

Oil pressure sender or coolant temperature sender ..... check to see if you've knocked one of the wires off when working on your heat exchanger.

 

[Tonic1]

Also, on my 07 Pilot 34 the warning buzzer sounds for transmission fluid temperature. Switch is on back side of transmission.

 

[rgano]

I have said this before elsewhere and will reiterate it here, Mainship did us no favors when it forsook the Yanmar instrument panel with its discrete idiot lights. You can certainly look at the Faria cluster gauge my boat came with to check oil pressure, water temp, and voltage to determine what you might from these indicators, but it is so much better to have a red light with accompanying piezo-electric alarm to tell you EXACTLY what just went pear-shaped with the engine.

While you can build a homemade rig with individual lights for the Yanmar warnings (my 6LPA has six warnings), there is a ready made panel like I got for my engine at this site https://www.greatlakesskipper.com/sea-ray-boat-engine-alarm-panel-1887754-seaward-pb4865-yanmar-6lp.

While the nice modular plug of this panel makes it look like you could simply plug it into a matching socket on the engine wiring harness, I did not find a matching plug on the wiring harness. Additionally, I did not desire to eliminate the original piezo-only alarm, which meant that I needed to tee off the color-coded alarm wires at the aft end of the engine (see engine manual wiring diagram) and run wires from there to the alarm panel with diodes inserted in the lines (except the low oil pressure wire which is reverse sense to the other alarm switches) to avoid one alarm lighting all the lights in the panel.

Here is a photo of the installed panel.

 

[jefndeb]

I think I found it..i was a little low on coolant and it looks like this might be the fresh water coolant low level sensor??

I topped the coolant off and the buzzers stops 2 seconds after engine start..

Whew....

 

[Comodave]

The old KISS principle, when you work on something and you get a new problem, go back and check you work. Good job troubleshooting.

 

[rgano]

I think I found it..i was a little low on coolant and it looks like this might be the fresh water coolant low level sensor??

I topped the coolant off and the buzzers stops 2 seconds after engine start..

Whew....View attachment 96776

Yep, that's the low coolant sensor. If you want to test it, on a cool engine remove radiator cap and start engine. Then use a turkey baster or any siphon/pump of choice to pull the level down an inch or three until the alarm goes off. I have used jumper wires on the other alarm switches of the engine/tranny to test their circuit integrity. It's good to know where each is located and how it works.

 

[jefndeb]

There is another sensor on the inside of the fwd cap of the charge cooler that has internal float switch type..I guess that's a seawater alarm?..I noticed it when it was removed..pretty sure seawater goes through that cooler..

 

[Nomad Willy]

I have a Murphy Switch. It’s attached to the outboard side of the exhaust manifold. It suspends a float that is attached to a buzzer. When the coolant level gets somewhat low the buzzer sounds.

We were up Slingsby Channel anchored in Treadwell Bay. We pulled anchor and turned down Slingsby Channel. Soon after the turn the buzzer went off. Back to the anchorage. After quite a time I found a pipe nipple that had a slightly cracked tube. Didn’t have a spare nipple but after much digging about I found two big pipe nipples and a very short peice of spare hose the right size. Hose clamps and we were off down Slingsby Channel and out and around Cape Caution.

Without the Murphy Switch we probably would have had a steamy overheating engine just about the time we passed the Cape. Being fairly close to the rocks the engine quitting would have been a very big pucker factor.

The next time our engine quit .... it just quit. It was a fuel delivery issue. But I recommend the Murphy Switch as a very cost effective safety device.