Raw Water Pressure
- dcrahn
- Deck Hand

- Posts: 53
- Joined: May 28th, 2015, 5:31 pm
- Vessel Info: 1984 Carver 2687 Monterey
- Location: Springfield, GA
- Been thanked: 4 times
Raw Water Pressure
Typically, what pressure range do crank driven raw water pumps operate in, idle up to wide open throttle? I've been a little under the weather lately and have not worked on my project. So, it gives time to think about some improvements and search the web. I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.
- waybomb
- CYO Moderator

- Posts: 2745
- Joined: February 5th, 2013, 9:24 pm
- Vessel Info: 1995 Boston Whaler Rage15
1987 3697 Carver Mariner
1988 Cougar 46 Kevlar Vee offshore
1969 15' Glasspar / 1967 Johnson Electromatic 85 - Location: Saint Joseph,Mi
- Has thanked: 69 times
- Been thanked: 492 times
Re: Raw Water Pressure
I have no idea what design pressure would be, but I would also guess that it varies by rigging and exhaust design.
fwiw - I have 35psi relief valves on PV's engines.
fwiw - I have 35psi relief valves on PV's engines.
Thanks
Fred
1969 Glaspar Avalon /1967 Johnson Electromatic 85
1987 Carver Mariner
1988 Cougar Kevlar 46' with triple blown 572 ci
1995 Boston Whaler Rage
Past - 1988 2807, 1989 4207 Aft
Fred
1969 Glaspar Avalon /1967 Johnson Electromatic 85
1987 Carver Mariner
1988 Cougar Kevlar 46' with triple blown 572 ci
1995 Boston Whaler Rage
Past - 1988 2807, 1989 4207 Aft
-
Viper
- CYO Supporter

- Posts: 6266
- Joined: July 10th, 2015, 9:58 pm
- Vessel Info: 1989 Carver 3807 Aft Cabin
- Location: Ontario, Canada
- Has thanked: 475 times
- Been thanked: 1791 times
Re: Raw Water Pressure
It's a good feature to have but I would prefer monitoring the temperature at the exhaust instead. No matter what fails in the cooling system, an exhaust temp monitor/alarm will tell you right away that something has failed even if you have full water pressure after the pump. While monitoring pressure may not catch a problem in some areas, exhaust temps which are at the end of the cooling circuit will react immediately no matter where the failure is. They're on my bucket list for the engines and generator.
- dcrahn
- Deck Hand

- Posts: 53
- Joined: May 28th, 2015, 5:31 pm
- Vessel Info: 1984 Carver 2687 Monterey
- Location: Springfield, GA
- Been thanked: 4 times
Re: Raw Water Pressure
Viper wrote:Qr Bbpost
It's a good feature to have but I would prefer monitoring the temperature at the exhaust instead. No matter what fails in the cooling system, an exhaust temp monitor/alarm will tell you right away that something has failed even if you have full water pressure after the pump. While monitoring pressure may not catch a problem in some areas, exhaust temps which are at the end of the cooling circuit will react immediately no matter where the failure is. They're on my bucket list for the engines and generator.
Agreed! I have 8 EGT sensors in my race cars headers that are recorded with my Racepak Datalogger. I check that very closely after every pass. But, I would still like to know what the raw water pump is doing.
- g36
- Admiral

- Posts: 2115
- Joined: April 7th, 2014, 6:07 pm
- Vessel Info: 1997 Carver 405
- Location: Soddy Daisy TN.
- Has thanked: 7 times
- Been thanked: 654 times
Re: Raw Water Pressure
fwiw an easy exhaust temp monitor i have nmea network on my boat and took 2 temp sensors put them on the exhaust outlets renamed them such and monitor the temps easily and can set alarm points to be notified of issues earlier than the temp guages show
1997 Carver 405
Crusader xli
The Black Pearl
Soddy Daisy Tn.
Crusader xli
The Black Pearl
Soddy Daisy Tn.
- bud37
- Admiral

- Posts: 5182
- Joined: April 23rd, 2015, 10:22 pm
- Has thanked: 604 times
- Been thanked: 1312 times
Re: Raw Water Pressure
dcrahn wrote:Qr Bbpost Typically, what pressure range do crank driven raw water pumps operate in, idle up to wide open throttle? I've been a little under the weather lately and have not worked on my project. So, it gives time to think about some improvements and search the web. I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.
Where are you thinking to tap the gage into ? The system is open ended so readings will be greatest at the pump outlet and probably close to very little at the exhaust manifold mixing point IMO. Small scale would again IMO give you the best shot at seeing variables.....hope you are feeling better........

FWIW.....The above is just my opinion.
- dcrahn
- Deck Hand

- Posts: 53
- Joined: May 28th, 2015, 5:31 pm
- Vessel Info: 1984 Carver 2687 Monterey
- Location: Springfield, GA
- Been thanked: 4 times
Re: Raw Water Pressure
bud37 wrote:Qr Bbpostdcrahn wrote:Qr Bbpost Typically, what pressure range do crank driven raw water pumps operate in, idle up to wide open throttle? I've been a little under the weather lately and have not worked on my project. So, it gives time to think about some improvements and search the web. I want to add a pressure gauge to my dash so I can keep tabs on what the pump is doing.
Where are you thinking to tap the gage into ? The system is open ended so readings will be greatest at the pump outlet and probably close to very little at the exhaust manifold mixing point IMO. Small scale would again IMO give you the best shot at seeing variables.....hope you are feeling better........
I am converting to a 1/2 freshwater cooling system and was thinking about somewhere between the raw water pump and the heat exchanger.
- bud37
- Admiral

- Posts: 5182
- Joined: April 23rd, 2015, 10:22 pm
- Has thanked: 604 times
- Been thanked: 1312 times
Re: Raw Water Pressure
I have an idea....might be a bit anal but.......I might wait until the system is up and running with all new stuff ( impellers etc ) and get a temporary gage and tap some different spots to get readings, then choose a gage to fit, lets say 0-15 or ??....that way you can monitor degradation fairly accurately .....just spitballin....
FWIW.....The above is just my opinion.
- bud37
- Admiral

- Posts: 5182
- Joined: April 23rd, 2015, 10:22 pm
- Has thanked: 604 times
- Been thanked: 1312 times
Re: Raw Water Pressure
bud37 wrote:Qr Bbpost I have an idea....might be a bit anal but.......I might wait until the system is up and running with all new stuff ( impellers etc ) and get a temporary gage and tap some different spots to get readings, then choose a gage to fit, lets say 0-15 or ??....that way you can monitor degradation fairly accurately .....just spitballin....
Kinda like pressure in the slicks 0-30 is useless if you are running 6.5......then 0-15.........woops hit wrong doodad. you get the idea.
FWIW.....The above is just my opinion.
- dcrahn
- Deck Hand

- Posts: 53
- Joined: May 28th, 2015, 5:31 pm
- Vessel Info: 1984 Carver 2687 Monterey
- Location: Springfield, GA
- Been thanked: 4 times
Re: Raw Water Pressure
bud37 wrote:Qr Bbpost I have an idea....might be a bit anal but.......I might wait until the system is up and running with all new stuff ( impellers etc ) and get a temporary gage and tap some different spots to get readings, then choose a gage to fit, lets say 0-15 or ??....that way you can monitor degradation fairly accurately .....just spitballin....
My thoughts exactly! Even though the impeller in the pump looked okay, I replaced it away and I hope to in the very near future fire the engine up in my shop and check everything before it's installed in the boat.