Yanmar 3YM30 - 'stop' button while cranking engine

[daggo]

Hi there:
After a longtime of not running the engine, Yanmar recommends that you crank the engine without starting for 5 seconds to get the oil dispersed. You're supposed to hold down the 'stop' button while cranking the engine so that it won't fire. But mine fires anyways.

Curious to hear others' experiences/comments.

[skipperpete]

Originally Posted by daggo

Hi there:

After a longtime of not running the engine, Yanmar recommends that you crank the engine without starting for 5 seconds to get the oil dispersed. You're supposed to hold down the 'stop' button while cranking the engine so that it won't fire. But mine fires anyways.



Curious to hear others' experiences/comments.

Well I guess it can’t do any harm to bring up the oil pressure with 5 seconds of dead cranking.
There’s a bellows on the stop solenoid at the aft end of the injector pump that’s called the “emergency shutdown” for use if the electrical circuit to the stop solenoid fails. Push that bellows in and have an assistant operate the starter. Be careful not to crank for too long, it’s possible to flood the exhaust with seawater.

[Wotname]

Originally Posted by daggo

Hi there:
After a longtime of not running the engine, Yanmar recommends that you crank the engine without starting for 5 seconds to get the oil dispersed. You're supposed to hold down the 'stop' button while cranking the engine so that it won't fire. But mine fires anyways.

Curious to hear others' experiences/comments.

Presumably your 'stop' button functions normally when the engine is running (otherwise you would not be able to stop the engine). So this suggests to me the 'stop' function is failing at the lower battery voltage that occurs during the start phase.

Whether this is real problem or not remains unknown but I suspect it is the early stages of a developing electrical problem - either with the battery (i.e.too low cranking volts) or with the stop solenoid (not operating at say 10V).

[sailormed]

I use the mecanical stop button that is on the engine. The electrical one on the control panel is without effect when starting the engine. 3JH4E engine.

[daggo]

Is there a mechanical stop button on the 3YM30? I can't seem to find a reference for that.

[daggo]

Originally Posted by skipperpete

Well I guess it can’t do any harm to bring up the oil pressure with 5 seconds of dead cranking.
There’s a bellows on the stop solenoid at the aft end of the injector pump that’s called the “emergency shutdown” for use if the electrical circuit to the stop solenoid fails. Push that bellows in and have an assistant operate the starter. Be careful not to crank for too long, it’s possible to flood the exhaust with seawater.

Are you saying it's not common practice to do this after a long period of not running the engine?

[skipperpete]

Originally Posted by daggo

Are you saying it's not common practice to do this after a long period of not running the engine?

I can’t speak for the entire boating community but from my own experience it’s not really common practice. Having said that, I hate starting (lube oil) dry engines either after rebuild or after long layup periods so I use an accumulator full of engine oil to prime ( or to fill) the lube oil system through the main gallery access points.
Many engines take at least a few seconds to flash up after a long period of inactivity so that period of cold cranking does pretty much what you say Yanmar is suggesting.