Water Pressure

[will941s]

Just picked up a 1997 Johnson 115, got her running (rebuilt carbs, replaced ignition switch, replaced neutral switch), I am about to replace the water pump, and my question is, what should the water pressure be? It reads about 10 psi at idle now.

 

[Monte1961]

Re: Water Pressure

Where are you getting that reading from? the peepee tube?

 

[will941s]

Re: Water Pressure

Yea, thats where it ties in

 

[Monte1961]

Re: Water Pressure

Well that is sufficient. The only thing i would be concerned about, is how old is the impeller and is it ran in saltwater. post back

 

[will941s]

Re: Water Pressure

Thanks, I am going to replace it. I just wanted to see if there was a specific mark it should be hitting with the pressure. It seems to be doing well, but judging by the parts on the motor that are original...and shouldve been replaced a long time ago, it's getting a new one. This is the first Johnson I have ever owned, so im still getting to know it. Also, am I safe to assume this motor does not have t-stats? It has water jackets that bolt to the actual heads, but I don't anywhere for a t-stat to go.

 

[Monte1961]

Re: Water Pressure

If it's not a C-model it won't have it!

 

[DDawg]

Re: Water Pressure

10# should be fine at any speed.
In gear at idle it may go lower, but when running on pad you want to keep it at 10 or above.

 

[Silvertip]

Re: Water Pressure

Anytime you buy an engine the first step should be to replace the impeller. The water pressure you have then is your benchmark. Any deviation in the future is then an indication that it needs attention. What you have now may be an indication that the current impeller is due for replacement. Replacement eliminates "guesswork"

 

[Chris1956]

Re: Water Pressure

My '98 Johnny 150HPV6 (60*) has 20+PSI at medium throttle. It pegs the gauge at high RPM. Just a data point. It also has 2 thermostats. I did not think any Johnnyrudes lacked thermostats. You might look harder on the heads.

 

[will941s]

Re: Water Pressure

Thats whats got me, I even looked up diagrams on the motor and nothing. They are not even in the parts listing. The water jackets on the heads are just flat. Like monte1961 said, on the "c" model it has the caps on the heads with the t-stats underneath them.