2012 175 ProXS normal water pressure

[Trask55]

What should the cooling water pressure be at idle, middle throttle and WOT? After 15+ minutes at WOT then going back to idle the cooling water will start rising rapidly and exceed 190 degrees. When I increase the engine RPM a little above idle I don't see the rapid spike in temperature. I have a Merc Monitor so I can see the water pressure but need some numbers to see if what my motor is doing is normal or in need of a water pump rebuild.

[potomacbassin]

You're gonna get nailed for not having your SN in here so you should try to get that. When was the last pump replacement? Don will likely tell you to start with the source (pump). Get the entire kit as it's the most economical and has everything that you need.

[SilverFox579]

You're gonna get nailed for not having your SN in here so you should try to get that. When was the last pump replacement? Don will likely tell you to start with the source (pump). Get the entire kit as it's the most economical and has everything that you need.

^^^^

While you get your SN as advised, water pressure should be 1 - 3psi idle and at least 12psi WOT. If the water pump is more than a year old, it's due for service which is recommended annually or 100hrs whichever comes first.

[leonreno]

Could also be thermostats that are not opening or could be strainer to compressor is clogged.

[Trask55]

You solved my problem! PSI at idle is .3 to .5 psi and 8-9 psi at WOT. The motor is used and new to me so I have no idea when the pump was last replaced. Not sure why I would need a SN for a question like this?

^^^^

While you get your SN as advised, water pressure should be 1 - 3psi idle and at least 12psi WOT. If the water pump is more than a year old, it's due for service which is recommended annually or 100hrs whichever comes first.

[Trask55]

Already replaced the thermostats and compressor strainer.

Could also be thermostats that are not opening or could be strainer to compressor is clogged.

[Trask55]

Serial number is 1B917726, Model is 1175P83HY. Anybody know what the Mercury part number is for the waterpump rebuild kit. I live in Oregon and would like to pick one up locally so I can get back on the water this weekend for spring Chinook on the Willamette River.

You're gonna get nailed for not having your SN in here so you should try to get that. When was the last pump replacement? Don will likely tell you to start with the source (pump). Get the entire kit as it's the most economical and has everything that you need.

[leonreno]

Definitely sounds like you need a new water pump. Serial numbers help because it’s not always easy to know what motor is being talked about. Some model years could have a carbed, EFI or Optimax models. Could also be 2.5 L or 3.0 L which all maybe different in certain ways. Also, ssome of those who help are Mercury dealers and can list the most accurate parts you might need. Hope you get it fixed before this weekend and can enjoy it.

[SilverFox579]

You solved my problem! PSI at idle is .3 to .5 psi and 8-9 psi at WOT. The motor is used and new to me so I have no idea when the pump was last replaced. Not sure why I would need a SN for a question like this?

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Edit to add, there are only two specifications for water pressure, idle and WOT, everything else is just "between".