1994ish Merc 454 operating temp?

[weekend warrior]

A long story short! the boat (1994 24' searay bowrider) has been laid up since 2009 due to various surgeries over the last 2 years. After the usual 2 year lay up issues, i replaced the impeller last5 week (old one looked perfect (was replaced the beginiing of 2009 also) and just replaced the thermosatat with a 160 deg today. I ran the boat with the new impeller to test for leaks and it ran well at about 170-180 deg with a thru-hull water connector that hits the intake hose prior to the water pump.

Today i replaced the tstat with a 160 deg for fear that the old one was cruddy. I was right. I cleaned the housing real well and replaced the tsat with a mercruiser 160 kit. Some idiot must have stolen the gasket with the metal eyes from the package in the store. From what i understand, the only importance of that gasket is for the audio alarm. It has not worked since i got the boat, so I assume the regular gasket will be fine. I ran the motor with muffs this time because the thru-hull connection broke as i was hooking the hose up. It ran between 170-190 for about 10-15 at idle rpms.

Well so much for a long story short, but i guess my question is: Is that a normal operating temp with muffs on and should i expect a lower temp in the actual water? Also, i believe the old tstat was a 170 and, if i remember correctly, I had a similar operating temp issue in 2009.

The engine was rebuilt in 2008/2009 (thats a whole other story) and has about 15-20 hours on it since the rebuild.

Thanks

 

[Failproof]

Re: 1994ish Merc 454 operating temp?

Those eyes are for conductivity. They not only provide ground for the temp sender but also to ground the housing from electron scavenging (corrosion) they are a good thing.

 

[weekend warrior]

Re: 1994ish Merc 454 operating temp?

Thanks! I will grab one tomorrow. That explains why someone stole it from the package!

 

[weekend warrior]

Re: 1994ish Merc 454 operating temp?

Now i'm pissed. i go the new gasket and simply replaced the gasket today. When i ran with muffs to check for leaks, the engine climbed to 200 deg and i shut it down.

Yesteday it ran in the 180-190 range with muffs and a transom hose bid (used muffs after the damn bib snapped off).

Not sure what the heck happened from yesterday to today. the impeller is about a week old and the boat has not been run since testing after it was replaced. Yeterday, i replaced the tstat with a merc 160 deg. I was missing a the correct gasket but installed it anyway. when i replaced the gasket today, the entire old gasket was fine and came off easily in one piece.

Any thought what happened in 24 hours of non use. gain, the boat has not been launched yet due to a slew of minor issues.