Merc 90hp thermostat question

[truth74]

Hello, i have a 1993 90 hp 3cyl outboard oD237890.<br />i went to change out the poppet valve and thermostat the other day, and when i went to the dealer they list 2 different thermostats<br />1. 140 Degree<br />2. 120 degree<br />Which one should i use? I was also told by the mechanic to leave out the thermostat, that it is better to not have one, i do live in South Louisiana so not much cold running here, if that makes any different.<br />Thanks for the help.

 

[Clams Canino]

Re: Merc 90hp thermostat question

I'd use the 120 degree myself, particularly in light of the advise to run none at all. I mean 120 is closer to none than 140 right? <br /><br />No opinion as to "none at all", but I'd guess they run better at a consistant operating temp than being kept colder. I suspect warm up would suffer a lot without one too.<br /><br />-W

 

[rickdb1boat]

Re: Merc 90hp thermostat question

Not to discredit clams, but you really want that engine to warm up as soon as possible before the stat opens and reach operating temp quickly. Make sense? Just like a car. If I'm wrong, please correct me. ALWAYS run a T-stat, no matter if the water is 100 degess that you run in. Any mech, that tells you to leave it out, is not a good mechanic...

 

[Clams Canino]

Re: Merc 90hp thermostat question

No insult or discredit taken at all. <br /><br />I registered no opinion as to pulling the thermostat followed by adding an afterthought opinion (LOL) that it would be harder to get it properly warmed up. <br /><br />I just hesitated to absolutely refute his mechanic from lack of my familiarity with the quirks of the 3 and 4 cylinder loopers.<br /><br />-W

 

[dilligafda]

Re: Merc 90hp thermostat question

Actually, the engine will idle better with the 140 t-stat installed, regardless of climate. You definately want one in.<br /><br />Just another opinion.

 

[Elmer Fudge]

Re: Merc 90hp thermostat question

Hi Diesel, the motor was designed to run with a t/stat,the proper operational temp is important if you want to get the best engine performance, it will also allow the motor to run cleaner and not foul the plugs

 

[LubeDude]

Re: Merc 90hp thermostat question

If I went to a "Mechanic" that told me to remove the thermostat in my engine, Id say "ya Right" and walk out and never go back! They are there for a reason and youve been told what that is!!

 

[truth74]

Re: Merc 90hp thermostat question

I Appericate all the help, and i agree with you, i am a Diesel Mechanic myself, but i usually work on 900 hp Cat diesels, not a little 90 hp outboard so i was no sure. Figured i would ask everyone here to see what they thought, as always i appericate the help, and thank you, i guess i will head to the dealer tomorow andget me a new thermostat.<br />thanks again<br />Richard