Do all boats have seacocks for the raw water cooling system?

[QBhoy]

What makes you think water can’t pass the impeller on an out drive ? It certainly can.
Try taking the intake hose of the front of a mercruiser and holding it down in the bilge below the water level on hull. It will definitely run water at an alarming rate. Should this hose be ruptured or trouble.
With merc bravo or VP outdrives the pump is on the engine. Take the hose off the often, lower than water level on hull, water pump and it too will fill your boat quick

 

[benchmark]

What makes you think water can’t pass the impeller on an out drive ? It certainly can.

On an Alpha gen II Z drive , water can NOT pass the impeller if it’s not rotating , I have tested it myself.

 

[QBhoy]

On an Alpha gen II Z drive , water can NOT pass the impeller if it’s not rotating , I have tested it myself.

Hi
I’ll hsve to strongly disagree with there I’m afraid. If you take the intake hose from the drive to TStat off and hold down low into the bilge....it will certainly run water out it if the hose end is lower than the water outside the hull.
Anyway. Not worth arguing over

 

[[2068]]

The raw water pump should be just above the water line.

Yes, on an SC35 / D4-260 DPH it is.
I replaced an impeller - not much water comes in if you quickly tie up the intake hose that connects to the pump, but you don't have to lower it much for the water to come in.

I think the problem with adding a seacock to most sterndrive boats would be that you'd be adding "something that can fail" in a location that would be very hard to access for maintenance or in the case of disaster.

 

[simonfraser]

Lol, well next job is to change the impellors so I'll be taking their covers off very slowly.

take the lid off the strainer and remove the plastic cover on top of the strainer first.
that will drain just about all of the water out and there will be a minimal water leak when you remove the pump cover.
rinse any leaked water off as its salty ....

 

[spannerman]

I did not know Volvo was designed this way but the hose above the waterline does seem to be a smart idea . I have only owned Mercruiser alpha drive and I never worried about water ingress via the cooling circuit as much as I worried about water ingress in case of a failed bellow .

The bend has nothing to do with the waterline as on anything over 25ft the whole drive is usually underwater including the hose, the reason for the bend on all drives is so that there is enough slack to allow the drive to be trimmed up. Remove the inlet hose from the water pump on virtually any D4/6 and water runs in unless you tie it up while changing the impellor. Now I’ve guaranteed sleepless nights for owners with a tendency to worry! The only way to fit a seacock to Mercruisers with an engine mounted pump or Volvos is in the hose between the transom and the pump, but access is usually not good and you still have the bit of hose from the transom to the seacock. To be honest I have seen more boats have engine room flooding from leaks via the driveshaft bellows and exhaust downpipe bellows than the inlet hose failing, and they haven’t been that many, a dozen or so in 20+ years.