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.

so does anybody know what a 575sci is supposed to run temp wise with overdriven ( 3 1/4" pulleys) aeromotive fuel pumps and 7 lbs boost? 140* or 126*? I'll call Teague tomorrow since they sell the kit, but any advice would be appreciated. Mike

I dont know how else to but this. I depends on the tune in the ecm. The engine has to reach the proper temp or the ecm will just think the engine is still in worm up mode. If you want to call someone you need to call Mark @ Precision Marine on efi and tunning he is good. Also Dustin @ Whipple

Agree.

AZSM includes lower temp stats in their kit to reduce risk of detonation. Their kit does not use a chiller. If you have a chiller the detonation risk should be minimized, no need to lower engine temps.