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Where is the thermostate located
Bilito	#1  Posted on 06/01/11 - 8:25 AM
Member Posts: 91 Comments: 0 Joined: 05/20/11	1991 Merc 40 hp, 4 cylinder, two stroke, I cannot find the location of the thermostat housing anywhere, and in the manual under cooling systems it only shows me how to repair the water pump. Anyone know where it is? The water coming out of the pee hole is pretty hot. I can barely hold my hand under it.
whalerman	#2  Posted on 06/01/11 - 9:44 AM
Member Posts: 540 Comments: 5 Joined: 06/26/07	Go to the library and ask if they have a section with repair manuals for boat engines. You can either stay and research it there or check the book out for a couple weeks and do your repairs. Next best thing is to GOOGLE it. THOM : 1999 Outrage 18, 2012 E-TEC 150, 2012 EZ Loader trailer
Michael A	#3  Posted on 06/01/11 - 11:25 AM
Member Posts: 23 Comments: 0 Joined: 04/14/11	Why not just look at one of the online parts diagrams for your motor? http://boats.net or www.mercruiserparts.com
Finnegan	#4  Posted on 06/01/11 - 12:26 PM
Member Posts: 1926 Comments: 16 Joined: 05/02/08	Those old classic 40-50's may not have a thermostat. I know that the classic in-line sixes 90-150HP don't have one.
Bilito	#5  Posted on 06/01/11 - 4:01 PM
Member Posts: 91 Comments: 0 Joined: 05/20/11	1991 is already called a classic????
Finnegan	#6  Posted on 06/01/11 - 10:18 PM
Member Posts: 1926 Comments: 16 Joined: 05/02/08	I believe that the design of the 4 cylinder 50 HP engine, later changed to 45HP and then 40 HP, dates to 1963. As you can tell by the length of it's run, it was one of Mercury's great 2-strokes.
Bilito	#7  Posted on 06/02/11 - 6:57 AM
Member Posts: 91 Comments: 0 Joined: 05/20/11	I just got it with the 91 whaler 13, and it is a smooth running quiet engine especially at idle or slow speeds.
Tom W Clark	#8  Posted on 06/02/11 - 7:06 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	The 1991 Mercury 40 does not have a thermostat.
Bilito	#9  Posted on 06/02/11 - 9:43 AM
Member Posts: 91 Comments: 0 Joined: 05/20/11	Thanks for that info Tom, the guys at iBoats just told me that too