The volume of seawater cooling

[tranmkp]

I suspect this would be the same for all inboard installations, D3, D4

Idling and underway at slow speeds, looking through the clear glass at the top of the raw water strainer. I seem to see a small amount of water and interest so at the bottom does that match what you’re saying while underway?

Perhaps I am expecting to see something like an air conditioning, site glass all for me and full of bubbles to the top.

I haven’t looked at the strainer under speed as I’m usually alone, and that could be tricky…

I have experienced zero cooling issues, in fact, taking it out in the Pacific ocean alone half a tank of fuel, empty waste tank, clean bottom and no dinghy or outboard on the back I was doing 22.5 kn at 4100 RPM - 192 temp on the Volvo D3.

So, the idea is if the volume is supposed to be an inch or so in the raw water strainer when I’m putting the boat to bed if I fill up the strainer to the top with the Volvo anti-salt, secret sauce, and keep it filled while running - (until is comes out the exhaust) am I increasing the chance of a Hydro lock?

Cheers

 

[Cutwater28GG]

I was intrigued by the water flow at speed as the intake is small.

My sight glass shifts from a solid water whirlpool to an effervescent bubbling cauldron once the revs are ramped up. It’s quite surprising how much aeration there is in the raw water intake.

 

[Just Right]

When under way does your head loose its prime? If so, you need to service the check valve. if the check valve is not holding it could allow air to be pulled through the head fill line. I replaced mine with a swing check valve from McMaster Carr. I also relocated it in a more vertical position above strainer low as possible so that it would have more head pressure keeping the valve closed. My head functions the same whether the engine is off, idle, or underway.

By the way, I tried a spring loaded check valve and it didn't work. The pump was not strong enough to open the valve.