Yanmar 3GM

[jfkal]

Strange, once in a while the oil pressure lamp stays on for up to 15 seconds and only then goes out. Most of the time pressure is fine right from the start. Oil level is normal and boat is not heeling. So far only happened with a warm engine.
Any ideas?

 

[Omatako]

I think it's a standard feature of the 3GM to have a buzzer and a light, I know mine had both. I'm not sure if the two "appliances" are activated at different pressures. Seems unlikely from one switch.
My first thought runs to an intermittently faulty switch.
My second thought is a non-return valve in the filter which may be letting oil drain back to the sump when standing. The filter then has to be filled again before the pressure switches the light/buzzer off. Such a fault could be of the intermittent nature you're experiencing.

 

[jfkal]

Yeah buzzer and light are on the same switch. Light and buzzer are on. Will observe a bit more. Is a bit worrying though. Biting fingernails waiting for either the light goes of or the engine grinding to a halt /forums/images/graemlins/crazy.gif /forums/images/graemlins/crazy.gif

 

[AlanPound]

[ QUOTE ]
So far only happened with a warm engine.
Any ideas?

[/ QUOTE ]

I'm not an engine expert, but it seems to me that tickover oil pressure is likely to be less when the engine is warm (it is on my car), so it might take a bit longer to build up to the pressure required to trip the switch. Maybe a small (*small*, I said) 'blip' on the throttle would cause the pressure to come up a bit more smartly...

 

[awyatybw]

The manual says that you should prime the oil pressure if engine not run for 72 hours or so by turning it over a few times on the starter-motor with the stop handle pulled out before letting it fire. Even so, 15s seems a long time.

 

[jfkal]

Until recently the problem never happened and now it only happens with a warm engine. Cold start is always fine.

 

[jfkal]

I tried that but it does not come up any faster. :-((

 

[steve28]

it will be the pressure switch, i had the same on my 1gm10 yanmar, it also helps to bleed the air out from behind the switch.

 

[jfkal]

Thanks Steve,

I will check that.

Joerg

 

[B58]

Make sure you use the correct switch part number 124060-39452 this switch will sound the buzzer at 0.3bar check your oil pressure using a gauge for peace of mind. GM's do not have problems with thier oil pumps!