How much water pressure should I have?

[capt911]

Hello All,

I just bought a 1972 MX16 with a 1986 Mercury Black Max 135 and none of the gauges are working. First question is how much water pressure should I have max when it is running, from any of you with a similar engine? I want to order the water pressure gauge with the smallest scale practical so I can see the changes the easiest.

I see Sierrra makes some that are 0 to 30 and some go as high as 60. I am thinking the 0-30 would be fine unless someone tells me otherwise from practical experience.

For the most bang for the buck since I am on a budget but do not want to be cheap either I am buying the water pressure, tack as well as speedo all at once and would prefer they match and be fairly accurate.

Any suggestions on brands and pricing from any of you would be great as well. I just joined the site have not owned a Check since the mid 70's but getting back into it now. I will post pics of my mine when I get some good shots of it and have more time.

Thanks all Cap

 

[sonicss31]

Buy the 0-30 and you will be fine. You should be good with 12-20 a WOT. Remember that too much pressure can be bad too.

 

[ForbesZ]

Buy the 0-30 and you will be fine. You should be good with 12-20 a WOT. Remember that too much pressure can be bad too.

x2. I never saw more than 20 psi on my 1996 Merc 150 with a brand new water pump (not just impeller but the whole pump). If your pressure goes above 30 on a 30 psi pressure gauge it would suggest the cooling water is being restricted inside the motor.