Normal temp 5.7L Mercruiser Bravo 3

[Mr. Impulsive]

Hi,
Brand new to this forum but am a member of a Corvette forum like this which is invaluable. I just purchased a 97 SeaRay 250 Sundancer with a carburated Merc 5.7 Bravo 3 I/O. Can anyone let me know the normal temp that this should be running. When I took it out for the first time it ran above 170 and didn't come down. This was my brother's boat, meticulously taken care of. He had a new thermostat and body impeller installed before shipping it to me. I do not have the engine operators manual with the normal temp referenced in the regular owners manual. I have the merc sterndrive paperwork but it deals more with engine installation and start up rather than specs. I am going down to the boat today with an IR gun to test the temp at the thermostat gooseneck but need to know what is normal. I felt the thermostat housing the day I took it out and it felt cooler than 170 which makes me think it is the guage or sender. Any help to a newbie would be appreciated.
Don

 

[HT32BSX115]

Re: Normal temp 5.7L Mercruiser Bravo 3

Hi Don,

170 might be ok when running.

You should probably check it with the IR gun to verify.

Is it closed cooled or raw water?

Mine is closed cooled and runs right around 170-180 on the gage all the time.

If if gets any higher than that at high power settings, you should check the oil/power steering cooler for raw water pump impeller fragments from previous raw pump failures.

sometimes those pieces get stuck in the hose from the raw water pump discharge to the oil coolers.


It would be a very good idea to get yourself a #11 service manual for your Bravo III and one for your engine.

Check the "Adults Only" sticky for down-loadable manuals. I think they still work. Follow the directions at the top of the link.


Oops, sorry about that. That link is dead now.

Try http://www.boatfix.com/merc/mainmenu.pdf

And http://www.boatfix.com/merc/Techbk/techcov.pdf



Cheers,


Rick

 

[gadget73]

Re: Normal temp 5.7L Mercruiser Bravo 3

What he said. 170-180 sounds right for closed, somewhere in the 140-160 range for open system is typical. Also consider the guages in these are not quite gospel. You may wish to ask your brother what he remembers it running at to see if what you see is different or not.