If the sea strainer is opened to clean and you open the sea cock will water flood the boat. We are having an overheating problem. With the boat under way at a no wake speed it is fine but when you power up the engines over heat. Want to eliminate a blockage or a faulty sea cock.
Sea strainer
- Thread starter Sligo
- Start date
scoflaw
Well-Known Member
- Aug 10, 2011
- 6,395
- Boat Info
- 1999 Powerquest legend 260 sx 502 mag
2005 Baja 242 islander 496
- Engines
- 502 mpi Bravo 1
496 mag B1
Close seacock then clean strainer
MoonRiver
Active Member
YES water will/ should flood into the boat through an open seacock value and the strainer top off. I would suspect a worn-out impeller.
jmcdboater
Well-Known Member
- May 28, 2022
- 574
- Boat Info
- 1988 300 DA Sundancer
Vessel JIM’N’I IV
- Engines
- Twin 5.7L Mercs w/Alpha One Drives
Koehler KVA 4 Genset
I’m with @MoonRiver, the raw water impellers for engine cooling are probably at fault, do you know when they were last changed? How long have you had the vessel?
Gallf1
Well-Known Member
- Sep 26, 2018
- 316
- Boat Info
- 2000 Searay 380
- Engines
- Mercruiser 454 MAG MPI 7.4L
Custom Forward Hardtop
Whaly 270 Hard Dinghy, 4hp Honda
Bahamas Veteran
One of the first checks I do is is to close the seacock, then take the strainer top off and open the seacock to see how much water you actually have coming out of the open strainer. Without doing that, you have no way of knowing if something (grass, barnacles, plastic bag) has not gotten sucked up into the intake screen underwater or is causing a blockage between the intake and the strainer.
If you have a good flow then you know that it is clear.
As long as your seacock has been maintained and is operable, there is no danger.
If you have no maintenance records of when you last replaced the raw water impeller, then I would start there. If pieces of the rubber impeller are missing when you open the pump, you will have to find and remove them from the oil coolers and heat exchangers.
If you have a good flow then you know that it is clear.
As long as your seacock has been maintained and is operable, there is no danger.
If you have no maintenance records of when you last replaced the raw water impeller, then I would start there. If pieces of the rubber impeller are missing when you open the pump, you will have to find and remove them from the oil coolers and heat exchangers.
Port engine has a new raw water pump because it was leaking. We opened the old pump and the impeller was good. Both impellers were changed at the same time I’ll have to check the log for the date. Back to the sea cocks we took the covers off the sea strainer one at a time and opened the sea cock no water flowed into the boat. The sea strainers are above the water line should water still flow when both are open.
Jaybeaux
Well-Known Member
- Jan 3, 2016
- 2,060
- Boat Info
- 2006 Sea Ray 48
Naught On Call
- Engines
- Cummins QSC-540s with V-Drives
11 KW Onan Genset
No.
kindredspirit
Member
I don't think I have ever seen a sea strainer through hull that is above the waterline so something doesn't sound right here. Most sea strainers exit underneath the boat (far below the waterline) and water should pour out of these if they are opened with no top on them. Could they be clogged with grass, plastic bags, etc? If there is no water flow through these and the engines were started I would think your impellers will need to be checked again. They won't tolerate running dry for long.
wayne0
Active Member
My feeling too.
brewster16
Well-Known Member
Let me be clear...with the seacock open water should always fill up and over the sea strainer when you open it up. If it's not overflowing then something is blocking the way. If there is no overflow on both sea strainers then I'd be suspicious that your seacocks are closed. Do not run your engines until you figure this out.
Soulshine
Well-Known Member
A friend's old Chris Craft has the strainers mounted high enough on the stringers that they can be opened with no water entry.
I always wondered how this lack of pressure couldn't result in no water flow to the pumps. When opened, the water is about 1/4" below the rim of the strainer but above the outflow to the pump. Maybe that's why it works.
I always wondered how this lack of pressure couldn't result in no water flow to the pumps. When opened, the water is about 1/4" below the rim of the strainer but above the outflow to the pump. Maybe that's why it works.
mrsrobinson
Well-Known Member
Not knowing what the impellers looked like before you replaced them you could have broken bits lodged somewhere, heat exchanger for example or another raw water cooler. That turned out to be my issue.
