Thermostats.. PLEASE help !

Billfo

Petty Officer 2nd Class
Joined
Sep 12, 2009
Messages
189
replaced thermostats & pump/impeller ( had a high temp alarm). Ran into some trouble. Hope someone can offer some advice..

I would apprechiate any help...

Changed the thermostats & noticed that the old ones were STAINLESS STEEL & the NEW ones are BRASS...

I am pretty sure these are ORIGINAL as the paint was not broke off the bolts yet..( yr 2000 135 Optimax)

I got these from iboats. Here are the part numbers:

Sierra # 18-3553
Replaces Mercury/Mariner 75692

added info.
parts are listed on iboats as "V135 A904646 & UP 75692 18-3553 "
My serial number is OTO66263

Since installation,I read that the brass ones are 120 degrees & the Stainless are 142 degrees... Will either work or did I just install the wrong thermostats....)

Thank you very much...
 
Last edited:

Billfo

Petty Officer 2nd Class
Joined
Sep 12, 2009
Messages
189
Re: Thermostats.. PLEASE help !

I was thinking... I can not duplicate the high temp alarm in the driveway with the muffs due to the added water pressure can I.. I am a but concerned that I have the wrong thermostats installed.. I read somewhere that Optimax's run hotter.. With my new thermostats opening at 120 degrees... what will this do to my motor.. Make it run cooler ? Will that cause any damage ? The high temp alarm should not go off now should it... :confused:


replaced thermostats & pump/impeller ( had a high temp alarm). Ran into some trouble. Hope someone can offer some advice..

I would apprechiate any help...

Changed the thermostats & noticed that the old ones were STAINLESS STEEL & the NEW ones are BRASS...

I am pretty sure these are ORIGINAL as the paint was not broke off the bolts yet..( yr 2000 135 Optimax)

I got these from iboats. Here are the part numbers:

Sierra # 18-3553
Replaces Mercury/Mariner 75692

added info.
parts are listed on iboats as "V135 A904646 & UP 75692 18-3553 "
My serial number is OTO66263

Since installation,I read that the brass ones are 120 degrees & the Stainless are 142 degrees... Will either work or did I just install the wrong thermostats....)

Thank you very much...
 

sschefer

Rear Admiral
Joined
Nov 13, 2008
Messages
4,530
Re: Thermostats.. PLEASE help !

120's are for high altitude, 143's are for sea level up to 3500 ft. Part nr determines temp not the material. Stainless is for Saltwater engines and are 143's. Most Saltwater is found at Sea Level.:)
 

Billfo

Petty Officer 2nd Class
Joined
Sep 12, 2009
Messages
189
Re: Thermostats.. PLEASE help !

Now thats interesting... I guess I am ok then, thank you for the reply !
Bill

120's are for high altitude, 143's are for sea level up to 3500 ft. Part nr determines temp not the material. Stainless is for Saltwater engines and are 143's. Most Saltwater is found at Sea Level.:)
 
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