115 Optimax won't heat up!

[Peetee907]

Hi All,
My 2006 115hp Optimax (serial #1B372539) won't reach normal operating temperature at idle and the SC1000 smartcraft monitor beeps once (short beep) then the alarm and engine symbol appears. I noticed the temp is 105 when this happens and stays there and doesn't reach the normal 143 at idle. When i put the boat in the water last week, started up fine, reached normal temp, ran great but then on the way to the dock the beep /symbols appeared. Removed thermosat and poppit valve. All looked good. Themostat was closed. Got me stumped! Any suggestions on what to do next? I assume the alarm/engine symbol is telling me it's not reaching normal temps.

[06 SB]

Pull, clean and test the thermostat(s). I am not sure how many there are on that engine. If not sure or if it is easier, just replace it. They are not too expensive. The poppet may be stuck open as well.

When the engine does not come up to operating temperature, you are in danger of a cold seizure.

[Peetee907]

Haven't run beyond idle at this point. Was going to just replace the thermostat. Poppit is not sticking at all. Could this cause for the one beep and engine symbol to flash on my smartcraft monitor?

[EuropeanAM]

What is the WATER PRESSURE at idle speed?

[Peetee907]

Water pressure was 4.0 PSI I replaced the poppit and thermostat. Seems to reach temp at idle now. Will need to test run it and let you know results. Hopefully that simple fix did the trick. Thanks!

[Peetee907]

Test run and temp is fine. drops to 96 at high speed and rises to 143 at idle. Water presure was 4 PSI at start and upon returning to dock was 3.5PSI. All seems good. no beep or engine alarm.

[EuropeanAM]

Good job!