Mercruiser 3.0 stalls after breaking through waves/wake

[Joshto]

Hi,

Sometimes, when I hit taller waves, or I break through another's boat tall wake, particularly when part of the hull lands hard on the water, the engine stalls. It sputters (no explosion) and dies slowly (even if I quickly shift to Neutral). I can restart it immediately without issues,. I know there is no electric failure because as soon as the engine dies, the oil pressure alarm goes off (normal in the ACC position when the engine is off), and the engine starts right away.

I wonder if this is common on the 3.0L carburated engines? What could be causing it?

Cheers
Josh

 

[alldodge]

Just guessing but oil pump starts to pickup air which drops pressure below minimum, so motor is shut down

 

[Joshto]

Just guessing but oil pump starts to pickup air which drops pressure below minimum, so motor is shut down

Do you mean gas pump? Why would the sudden loss of oil pressure turn off the engine?

 

[Scott06]

I don't think oil pressure alarm shut off the engine. the alarm goes off when the engine dies and is still in run (assme you mean run not acc).

Willing to bet your key or more likely man overboard switch is cutting off the ignition. I had a similar situation when going WOT over waves. toggled the switch off then on and it worked. Try toggling the switch on shifter.

 

[Joshto]

I don't think oil pressure alarm shut off the engine. the alarm goes off when the engine dies and is still in run (assme you mean run not acc).

Willing to bet your key or more likely man overboard switch is cutting off the ignition. I had a similar situation when going WOT over waves. toggled the switch off then on and it worked. Try toggling the switch on shifter.

Correct. And my oil alarm is not wired to cut power if the oil pressure drops; it only goes off (audible).

I have a killswitch but the lanyard is connected all the time (the switch is always ON). I'll bypass it next time I'm out to see if the issue persists. Perhaps there is a loose terminal or contact inside the switch which flaps/disconnects quickly over waves.

 

[Scott06]

Correct. And my oil alarm is not wired to cut power if the oil pressure drops; it only goes off (audible).

I have a killswitch but the lanyard is connected all the time (the switch is always ON). I'll bypass it next time I'm out to see if the issue persists. Perhaps there is a loose terminal or contact inside the switch which flaps/disconnects quickly over waves.

I have seen them go with or without the lanyard, pull the lanyard off and reset or jumper around it.

 

[alldodge]

Do you mean gas pump? Why would the sudden loss of oil pressure turn off the engine?

I just took a WAG and wasn't thinking about the ignition of a 3.0 not ever having TBV ignition. Have EST oil pressure would not cause it. The other guys have you covered

 

[flashback]

My first thought is loose or corroded ignition wiring..

 

[Joshto]

My first thought is loose or corroded ignition wiring..

You are close.

Not sure if corroded but the actual ignition switch is the culprit. If I wiggle the ignition key a little while the engine is running, the engine stalls.

So there is the problem. We can close this thread