Do all motors have a thermostat?

[LORDY611]

First, on Independence Day I would like to thank all those who are veterans or who currently serve to keep us that way. My deepest gratitude.

I need to find out if my 94 Merc 40 hp 4 cyl, serial number 0g084106 actually has a thermostat. I have a Mercury Marine manual (on CD) that does not address it anywhere. I have done a visual inspection of the motor, and outwardly it shows nothing that appears a likely part. Can anyone tell me one way or another?

 

[LORDY611]

Re: Do all motors have a thermostat?

Any ideas from the Mercury Sages in the audience? My vacation in Maine is approaching and dont want to be stranded. Thanks in advance.

 

[emckelvy]

Re: Do all motors have a thermostat?

Your Classic 40 does not have a thermostat, as confirmed by the www.mercurypartsexpress.com site.

Are you having cooling issues? If so, I'd focus on the condition of the impeller/water pump assy and/or any blockages in the cooling system (which could be tested with the lower unit pulled, by running an external source of water up the copper water supply tube).

Anyway, if you've any specific issues pls post and likely we can help........ed

 

[LORDY611]

Re: Do all motors have a thermostat?

No cooling issues at this time. Motor has been sleeping for about 5 yrs and it was recommended by someone here that, among other things, I replace the thermostat and bypass valve. Just wanted to be sure. I think I'll also wait on replacing the plugs just on their age alone. Motor runs and purrs like a kitten. I'm playing this one as "dont fix it unless it's broke".
Thanks for your research, and I'm glad it matches mine.

 

[emckelvy]

Re: Do all motors have a thermostat?

Definitely change out the impeller since it's been sitting for so long.

Those are amongst the best (and just about the last) of the old 4-cyl Merc, they sure are a sweet running motor.

I have fond memories of one summer in the early 80's when my brother and I ran an old $25 MK 58 (45 HP) on a 13' flatbottomed wooden ski boat; what a great motor, never missed a lick!

Enjoy your Classic 4 !......ed

P.S. a little carbon-cleaning fuel conditioner such as Seafoam (if you can get it), Chevron Techron, or one of the outboard mfr's brand of the stuff, wouldn't be a bad idea either. It'll clean any carbon deposits out of the innards, and keep the carbs Sparkly Clean.