running........cool??
 

i had my boat out for the second time since replacing the impeller and thermostat. Ive noticed my engine hardly make it to 125 degrees anymore and when it does it doesn't stay there for long. it stays right about 100 degrees. I had it up to about 45 mph for a good 10 minutes today and still runs cool. there is no problems @ all with operation im just wondering if there is anything to be concerned with. before i did these repairs it was running around 140 to 160. i did install the 140 degree stat. any thoughts? maybe the temp probe in the engine is not reading right? or im i making a big deal about nothing??? i do go out of my way to flush the engine after 2 uses just to make sure all the river stuff is out.

Re: running........cool??
 

Mercruiser states 160 deg stat for the 5.7. If you run it to cool you start running the motor rich all the time , which leads to performance issues along with extra wear on the engine.
Try going back to the 160 stat and I think you'll be fine IMO.
Lets know Philly!!

Larry

Re: running........cool??
 

see thats mildly annoying b/c both the mercuriser dealership and the seloc book says that was the stat i needed was the 140 for the engine i have the 5.7 v8. however i just have that feeling that it wasnt right. no big deal it was only a 25$ part and did it myself. if i paid someone to do that it would have really been aggrivated. this makes me wiser.

Re: running........cool??
 

I have run into the same thing with the 4.3L. Might double check in the manual section here on MOC. You got the engine serial number handy? I can check for sure then.

Larry

Re: running........cool??
 

serial is OC867526. 5.7 l v8 in my 1990 xlc 2150. i also looked at the receipt and it is a 143 degree stat. rechecked my manual and it says anywhere from 143 to 160 degrees.

thank you for the help!

eric

Re: running........cool??
 

Heck , pull a plug Eric and see if shes running rich. If not maybe sender or gauge. No big deal.IMO run her like is if alls well :)

Larry

What is considered normal operating temp? Mine runs about 170 all the time. I think that's too cool but I'm new to boats. I've been resisting tearing into mine to investigate also.....

Sent from my SCH-I535 using Xparent ICS Tapatalk 2

Re: running........cool??
 

My 4.3 runs at about 170 all the time.

Re: running........cool??
 

that is kind of where mine ran too before i did the repairs. but a few friends of mine said there run 130 to 150 with the 5.7 and the 7.4 engine. engine is due for a tune up, new belts and a new intake hose so may replace the water temp probe cause i had to remove the wires when i replaced the stat.....im sure by touching something that hasnt been touched in 22 years messed it up.
in the meantime ill check to see how rich shes burning ....larry thanks for the help/ eric