Alarm in rough seas

[Bordeau]

It happened once last year and again this season. My 16ft Double Eagle is riding up and down the white cap waves and the engine alarm sounds on the 2004 60hp Mercury. At that time, I notice that the water pressure gage is not as stable as usual. It fluctuates from 5 to 20 psi.
On flat waters, all is good.
The cavitation plate is aligned with the bottom of the boat as per installation guidelines.
When the boat tips down over the wave, is the lower leg sucking air, reducing the water pump pressure therefore causing overheating?

 

[Rain City]

It happened once last year and again this season. My 16ft Double Eagle is riding up and down the white cap waves and the engine alarm sounds on the 2004 60hp Mercury. At that time, I notice that the water pressure gage is not as stable as usual. It fluctuates from 5 to 20 psi.
On flat waters, all is good.
The cavitation plate is aligned with the bottom of the boat as per installation guidelines.
When the boat tips down over the wave, is the lower leg sucking air, reducing the water pump pressure therefore causing overheating?

My kicker alarms when it revs too high in rough water.

 

[Macdeep]

Questions

1 - your 60hp outboard has a water pressure guage?

2 - does your outboard overrev or get beyond 6000rpm when your having this alarm go off in the waves?

3 - are we talking swell, or 1-2ft white caps or a combination? usually white caps dont result in the motor getting out of the water since the boat doesnt pitch that much and the hull mostly bridges the waves. Or are we talking bigger white caps like 3-5 footers where we're at the edge of what your 16ft boat can comfortably handle. May be it's a case of just not boating in that sort of conditions?

My last boat was similar to your set up, 16ft with a 50hp, and I never had issues with cavitation or lack of water to the water pump in either swell or decent white caps on either the west coast side (winter harbour) or the inside waters around Telegraph... and I've pushed that boat into some uncomfortable boating situations waves and swell wise... scared the **** out of myself and my crew once coming back from Grant Bay - never again in a small boat like that...

 

[Bordeau]

1 Yes, I installed an aftermarket water pressure gage.
2 It doesn’t overrev. The engine works the waves: harder up, easy down.
3 Waves 3-5 ft. I’m riding with wind coming from behind. They would be too big for my liking to go face first into them. The boat is rocking up and down. Although the prop does not seem to get out of the water, I’m guessing that it must be sucking air in while the bow is dropping.

The water gage indicates fluctuating pressure. It moves from to 5 to 20psi.
When the alarm sounds, I stop and turn off the engine. After inspecting the prop and hole intake, I resume. The water gage pressure moves up and stabilize for a few seconds before starting to fluctuate again as soon as we ride up and down.
On smaller waves, it is never an issue.
Maybe it’s a sign to get out of there or not to put myself in these situations.

 

[Macdeep]

1 Yes, I installed an aftermarket water pressure gage.
2 It doesn’t overrev. The engine works the waves: harder up, easy down.
3 Waves 3-5 ft. I’m riding with wind coming from behind. They would be too big for my liking to go face first into them. The boat is rocking up and down. Although the prop does not seem to get out of the water, I’m guessing that it must be sucking air in while the bow is dropping.

The water gage indicates fluctuating pressure. It moves from to 5 to 20psi.
When the alarm sounds, I stop and turn off the engine. After inspecting the prop and hole intake, I resume. The water gage pressure moves up and stabilize for a few seconds before starting to fluctuate again as soon as we ride up and down.
On smaller waves, it is never an issue.
Maybe it’s a sign to get out of there or not to put myself in these situations.

Do you have a boating partner to watch and see if the motor / water intake is coming out of the water, and to see if the tell tale is producing water as it should in these conditions?

Is the alarm from your aftermarket guage? or from the motor itself?

 

[Bordeau]

Yes water is coming out the tell tale but not steady and not at full pressure.
The alarm is from the ignition key box connected to the engine.

 

[SpringFever552]

Could it be a water sensor in fuel filter?
Leg oil sensor?
Wave action making it go on and off?

 

[salmonkiller01]

See if you engine fuel filter has a water sensor. Sounds like that is closest. Water pressure has no alarms just overheat I believe