Intermittent alarm 1GM10

[Boavebof]

I have just taken ownership of a 2nd-hand boat with a Yanmar 1GM10 engine. She has been sitting on dry land for about 4yrs and I took her for our first trip out yesterday. (Before I bought her I did a quick water test to make sure the engine ran and she didn’t sink but it was only 2 minutes).

Maybe 10mins of running on moderate engine, an alarm started going off on the control panel and a red light came on. I (slightly) panicked as hadn’t been able to see much water coming out of the exhaust and assumed that the alarm was because she was over heating so stopped the engine.

On looking closer it seems to be the left-hand light that came on (labeled “R. SEAL” on the panel but “SALTWATER (Saildrive)” in the manual) and I have given it a full going over in order to try to find the reason for the alarm but can’t figure it out. I have checked the salt-water strainer and change the impeller; there is now more water coming out of the exhaust but the alarm is still sounding whilst the engine is running. Can anyone advise why?

Of note, the alarm starts blaring when the key is turned and 2 lights come on (OIL and CHARGE - as they should). When I press the start button, the beeping stutters in time with the vibration from the engine and remains stuttering throughout (as the engine revs increase, so does the frequency of the stuttering. The light flickers at the same frequency as the alarm noise)

Any help telling me what the alarm is telling me and how to fix what is wrong; or alternatively just how to shut the bloody thing up, would be most appreciated.

 

[Daverw]

Is it on a sail drive or shaft drive? This panel can be on both, on a shaft drive the R Seal lamp not connected

 

[Boavebof]

on a shaft drive the R Seal lamp not connected

That’s what I thought. It’s a shaft drive. There must be some form of accidental connection that is being ‘bounced’ onto the live wire by the vibrations of the engine.

 

[Tranona]

First thing is to checck all connections, particularly the big one between the engine and the panel loom. There is a fuse in the loom which should also be removed and cleaned. when I had the same problem it was the sender unit that was faulty.

 

[Daverw]

 

[Daverw]

From the circuit diagram you will see to alarm they drop to negative so you could simply have a wire on the engine loom that has bad insulation and is touching engine block somewhere

 

[VicS]

Below is a schematic ( from the April 2018 edition of the owners manual) which includes the "water in saildrive" sensor and its associated circuitry.
#22 is the sensor, #10 is the amplifier, which I'd not expect to find in a shaft driven boat, and #6 is the warning light.

If I were the Op I would look around the engine compartment for the not-in-use wiring for the sensor which may be shorting .

The warning light and audible warning could be silenced by cutting or disconnecting the wiring I have highlighted.

BUT consider the possibility that the wiring and warning circuit could have been used for another purpose. An exhaust high temperature warning is an obvious possibility.

The intermittent nature of the alarm could be due to a bad connection including the fuse Tranona mentions (#16 in the diagram)

 

[Boavebof]

Hello all,

Just as an update: I got someone to look at the wiring and it looks like there was a short where the Saildrive wire had been cable-tied to the engine mount (apparently to keep it out of the way). Taped up, wrapped in foam and secured. Problem fixed.

Thank you all for the help.