575sci water temp
 

I just picked my 38' Scarab from Absolute S&M. They removed and replaced the intake on the port motor to replace a missing splash shield (that Derberry left out when they built the motor last year but thats a whole other post). Runs great and no more oil burning but on the sea trial after the repaired they said it overheated so they replaced the seawater pump impeller. Well, I took it out yesterday after I picked it up and running 45-60 mph the water temp runs about 130-140 (it ran about 115-120 before the repair) Now ,after running it for a while and returning it to idle the temp pops up to about 150 for about a minute and then settles down to about 120 ( like it did before the repair). The starboard motor stays at a solid 120 deg. Any ideas????

sounds like thats about right to me...110-120 seems to cold

that motor should have a 140 t stat unless it has the whipple upgrade

130 - 140 is what both of mine run. They will jump up a little after a run, but settle right back down.

120 seems very low for stock 140* thermistats...even for a 126* that is low. With 126* stat my 575 runs @ 132* or so. With the stock stat it ran just below 150*.

When I installed the 126* stat I drilled 3 1/8" bypass holes in the stat. It does not fluctuate in temp as much as it did with the stock stats.

Maybe I will try the 126* stats like you did,on both motors. What bothers me then is that both motors were wrong and acting exactly the same before the repair?

Go with 140* Tstats. There is no reason to run it colder.

What about with superchillers and 3 1/4" pulleys and running 7 lbs boost? Would that be a reason for running 126* stats?

You need to run the proper t stat for the ecm program you are running or it will run not run properly.

In that case, maybe. I thought you were talking stock 575sci's. Oil temps are more relative. How are they???? are you running crossovers or recirc pumps???
I had the boost cranked up to almost 8# on my 525SC and still ran the 140* Tstat and recirc pump. It maintained nice consistent temps from 145 at idle to 155 after WOT runs.