2005 mercury 150 optimax overheat alarm

[Acadianwife]

changed impeller last spring. Pissing fine, 2nd time taking it out on new impeller lake tahoe (fresh water) 7400 ft elevation. full throttle 3500 rpm 10 minutes long alarm turned on (overheat). turned off motor, turned back on. continued on at 10 miles per hour for the next couple of hours. At idle was pissing, but splattered warm water below **** hole plus some steam (white in color and dissipated within 1 foot). Water pressure gauge around 2 pounds at full throttle. The water pressure gauge needs 1500 rpm to even register. From reading all of the posts I am thinking poppet valve diaphram/spring along with a faulty gauge. I'm going to drop and take a look at the impeller to make sure it is seated fine. When I have the muffs on and a garden hose it does take almost a minute for the water to come out the **** hole. This boat has only been ran in Gulf of Mexico salt water and was maintained mostly in mexico I am the second owner. DFI Optimax digital saltwater #1B073182

 

[Don S]

Re: 2005 mercury 150 optimax overheat alarm

Here are the specs and troubleshooting help for your water pressure.

Water Pressure
Idle 1.0 ? 3.0 PSI
Poppet Valve Opening 4 ? 9 PSI
W.O.T. 12.0 PSI Minimum

 

[Acadianwife]

Re: 2005 mercury 150 optimax overheat alarm

Thank You! I will post what the cause is when I have a chance to open up the engine