Closed Cooled Merc 5.7 260 hp operating temp?

[dipthenet]

Hello,

I am in the process of breaking in a rebuilt Mercruiser 5.7. Can someone tell me what the correct operating temp should be? Thanks in advance.

 

[Bondo]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

Ayuh,... Depending on the T-Stat used,.. 140?, or 160?, or 180?.....

What are you seeing,..??

 

[dipthenet]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

125.

 

[Bondo]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

Ayuh,... Sounds like it's stuck open....
Is this in the pond, or on muffs,..??

If on the muffs, Splash it,+ see what it does...

 

[dipthenet]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

The boat is in the water. Current lake water temp is 59.4 degrees.

 

[HT32BSX115]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

Sounds like the t-stat is stuck open....

Mine runs at about 170-180 with a 160 'stat!

 

[dipthenet]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

Maybe a stupid question but I have to ask. What happens to the motor if you run it at too low of a temp? I understand the issues of running to hot.

 

[HT32BSX115]

Re: Closed Cooled Merc 5.7 260 hp operating temp?

It's not very efficient running any engine too cold..... Especially if it's an EFI engine. ...... It'll run really rich because the ECM will think it needs to provide rich mixtures for warm-up.

Make sure your engine IS actually running cold though, by verifying it with a known temp gage..... or IR "gun"...