4.3 liter mercruiser 2004 possible thermostat issue

[rrose002]

Hello everyone, I have been a member for sometime as a reader and I have found this place the most informing forum, Thanks to you all, So I have a 4.3 liter Mercruiser 2004 in a 2004 Searay with a possible thermostat issue. I would like to take out the thermostat and replace it if necessary.... My question is, do I have to drain a sea water cooled engine to do this? The reason I want to replace it, is that the engine used to run at 170F now it only goes to 135F. Thank you all

 

[Fun Times]

Re: 4.3 liter mercruiser 2004 possible thermostat issue

My question is, do I have to drain a sea water cooled engine to do this? The reason I want to replace it, is that the engine used to run at 170F now it only goes to 135F. Thank you all

Hi there, Is the boat out of the water and on a trailer?

Draining the engine block is not necessary on your sea water cooled engine model. Some water may spill into the bilge area when you pull everything apart but not much. Just have drain plug removed and the bow raised if possible to help keep things cleaner and dryer is all.

If the temp is only getting to 135 ever so slowly, then chances are the thermostat is held open by debris.

 

[Bondo]

Re: 4.3 liter mercruiser 2004 possible thermostat issue

Hello everyone, I have been a member for sometime as a reader and I have found this place the most informing forum, Thanks to you all, So I have a 4.3 liter Mercruiser 2004 in a 2004 Searay with a possible thermostat issue. I would like to take out the thermostat and replace it if necessary.... My question is, do I have to drain a sea water cooled engine to do this? The reason I want to replace it, is that the engine used to run at 170F now it only goes to 135F. Thank you all

Ayuh,... Welcome Aboard,.... To add to what Fun Times says, pay attention to the gasket with the brass rivet in it,...

Without it where it belongs, yer heat gauge, 'n alarm won't work,...