Yanmar ignition panel puzzle

[Sailor Sue]

Recently I've noticed the warning buzzer does not sound when turning the key to the pre start position. After the enginge has been running for a while and we shut it down the buzzer will sound. Yesterday when I had a few minutes I checked for loose wires behind the panel. I didn't find any, but I did notice that the buzzer would sound when I flipped the toggle button to test the buzzer. I'm thinking it might be a problem with the key switch. Any thoughts or comments? The engine is a 3JH2 series; the switch panel has the tach and 4 or 5 warning lights across the top. Thanks.

 

[Alan]

Yes, I had this issue years ago and just changed the switch. A quick & easy fix.

 

[Bill Roosa]

Check the name on the switch

Mine says "buzzer on-of.f" It is not a test. It is to turn the buzzer off when you have the "ignition" (diesel's don't really have ignitions) on for a while and don't want to listen to the buzzer.

 

[Benny]

It could be the key switch but sounds unlikely. The key switch is just a mechanical device to close an electrical circuit If the engine starts then power is going through the key switch to the solenoid push button circuit and the key switch is working fine. The fact that the buzzer is not responding is likely a fault in the sensors wiring or the buzzer itself. With the engine off there is no alternator charge and there is no oil pressure so the sensors should close the circuits to the buzzer and sound. By contrast the coolant temperature sensor will not activate the buzzer wether the engine is on or off until the temperature reaches a set temperature. For that reason your panel has a test switch so you may test the buzzer when the engine is running and check to see if the temperature light goes on and the buzzer sounds. I suspect that your wiring harness may be aging and there might be a drop in voltage until the running alternator raises the voltage to allow the buzzer to operate. The other possibility is that the buzzer itself is starting to go or a combination of both factors. By the way does the buzzer sound sharp and strong or is it starting to screech? Hope is not the buzzer as it is quite expensive. A sailor I know replaced his with one from a Jet Ski and hooked it up to the oil pressure circuit and installed a coolant temperature gauge and an ammeter for the charging circuit to supplement the idiot lights. Good luck and let us know what you find.

 

[Bob Mack]

I had a "similar but different" problem with the ignition switch on my 2007 B373 with the 40 HP 3JH4E. In the Spring of my 3rd year, I found the ignition switch appeared to fail.

I diagnosed a switch failure, but decided to disassemble the switch to identify the nature of the failure before replacing. I determined the switch could be disassembled. Turned out that the contacts and plate had been over lubricated when the switch was manufactured. I cleaned off the excessive lubricant, cleaned the plate and contacts, lubricated lightly and reassembled the switch. It has operated perfectly since.

Yanmar owners may want to consider this possibility when a switch related problem appears.