As y'all know, when you first turn the key to start the engine (Yanmar 3gm30F) the high temp alarm sounds. This is a test so you will know it's working. Recently that stopped happening. Now I get silence when I turn the key. The question is: what broke? The switch? The temperature sensor? Is there a way to chase it down? I hate to be running around with no high temp alarm. Thanks for any insight.
High temp alarm no longer sounds when I turn key.
- Thread starter markwbird
- Start date
I think that it is actually the oil pressure alarm that sounds. Check the wiring. Start at the engine, as it will easier to find. there should be a fitting somewhere on the side of the engine where the sensor is screwed in. Check to see that it is still connected. The high temperature sensor will be located near the thermostat housing. When you find it, you might just as well see that it is still connected.
On the back of the key switch there will be 3 lugs, one will receive power from the battery, one will provide power to the alarm and idiot lights, and the third is probably a momentary switch for the start circuit. Check to see that there is power at the switch and at the lug that powers the alarm.
Sometimes the oil pressure sender fails and needs replacing.
On the back of the key switch there will be 3 lugs, one will receive power from the battery, one will provide power to the alarm and idiot lights, and the third is probably a momentary switch for the start circuit. Check to see that there is power at the switch and at the lug that powers the alarm.
Sometimes the oil pressure sender fails and needs replacing.
That was my understanding as well. I think the alarm sounds before you start the engine because the ignition is on an there's no oil pressure. The fact that this allows you to test the alarm is just a handy side effect.
Mine wasn't working when I launched this year. It was a crap in line fuse holder near the engine that came apart. +1 for pressure alarm.
Allan. Yes. The alarm still sounds when I activate the toggle switch. Good call. Thanks. So I had a sort of bizarre incident with the engine as I took guests out on the 4th. The hose running from the heat exchanger to the exhaust elbow was a bit long (my fault) and it rested atop the air intake. Vibration wore a hole in it and it sprang a leak. Water shot out of the leak and into the air intake. The engine started running rough and weird and kept quitting. I finally figured it out and fixed it and the engine seems fine now but no oil pressure sensor alarm. Boats! Ya know what I mean?
In your mucking about fixing the hose, you may have inadvertently disconnected the oil pressure switch or damaged it. Find it and check to see if it remains connected.
I gave the engine a visual inspection once I shut it down and both water and oil seemed good, coolant level in the reservoir was just at the LOW line. Once we were done sailing I poured a little Dawn dish detergent in the impeller inlet and started up the engine to ensure that I had flow through the water pump and had a positive indication. We motored back to the marina with no further issues so I'm hoping this was a false alarm but I would feel much better if I had gauges to tell me more about what is going on in my little 2YM15. And No, I do not normally run my engine at 4,000 RPM, its usually pushing 2,500 on the way out and back but the wife wanted to go waterskiing that day.