Engine temperature.

[sogood]

Apologies if this is a little bit vague, but I'm wondering what temperature a 5.7 Mercruiser should run at. What's the max that should show at the gauge on the dash? I'm still refurbing my Wellcraft and will be working on the engine soon, running it on muffs and want to know what I should expect.
I haven't gotten around to sourcing the model number, but it's a 1990 V8 with an Alpha 1 leg, if that helps at all.

Thanks in advance.

 

[harleyman1975]

my 5.0 (chevy) engine on my 2003 runs at 175. the 302 (ford) I used to have ran at 140. I would say that any consistent temp in between there would be acceptable.

 

[alldodge]

1990 V8

With a carb it should be 140 degree thermostat. Under a hard run it may get up to 160 but when idled back down should return to around 140 to 150

 

[Scott Danforth]

change the impeller if you havent done so yet. also, the dash gauge may or may not be close to actual temp, use an IR temp gun to determine real temp

However at AD indicated, carbed motor would be 140 degree unless it has a heat exchanger

 

[sogood]

Thanks for the responses. I have a new impeller for it, which will be fitted as part of the "to do" list. Thanks again.

 

[harleyman1975]

Good luck! let us know if that fixes it.

 

[sogood]

Thanks Harley, but I'm not looking at a "fix" as such. I'm giving the entire boat a bit of a refurb and was just wondering what sort of operating temperature I should expect. I've seen/ heard the engine running on muffs, for a short while and it really ran sweet, having had a lot of work done on it prior to sale, including a rebuilt carb. Thanks again.