1999 350 Mag - Higher SB Temperature

[HighFlight2k2]

As I said in my other post, this weekend is diag weekend. Next on the list is that according to the computer (I have the diag software), my Port engine runs at around 174 degrees but my SB is running around 188...this while at ~3500+ RPMs. Once the RPMs are down to no wake speed, both temperatures around between 165 and 167. I'm not sure if this rules out the sensor or not.

The impeller in the SB engine is newer than the Port.

So my first thought is to change the thermostat. It's in the housing circled correct? I also am going to ensure the strainer is clear. Any other thoughts?

Thanks so much.

Jon

 

[HighFlight2k2]

Sorry...accidental reply.

 

[obsessive]

Yes on the thermostat location.

Our boat (350 SB) runs around 175 underway and 170 putting around.

Was it run dry at some point when it was out of the water, this could be an issue as well.

 

[HighFlight2k2]

Definitely didn't run it dry.

I guess I'll start with thermostat and sea strainer. Maybe sensor swap...but being that the temp comes down with RPM drop I don't think that's the problem. Does the engine have to be up to temperature to bleed the air?

 

[obsessive]

Your engines have raw water cooling, correct? Or, are they a closed system like in a automobile with a heat exchanger?

A thermostat likely would cause severe overheating or the inability for the engine to reach operating temperature. A clogged strainer could cause the issue you're having.

 

[HighFlight2k2]

Fresh water cooled with a heat exchanger. I hear ya with the thermostat. It's so cheap though I'm just going to do it to rule it out. But I don't have high hopes for it. Crossing my fingers for the strainer or the sensor.

Thanks.

 

[HighFlight2k2]

Well, no luck with this one. Changed the thermostat and ensured fluid levels were correct. It's still running around mid to upper 180s.

Curious about the sensor(s). There seems to be 2. One sub a singers wire and one with two. I assume the one with just one wire is for the sea ray alarm and the other is the one for the engine. Is that correct? Is it with changing that?

Jon