Overheat alarm 1991 Evinrude 90hp

tnduc

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After being stored for over a year I got the boat out and cleaned it up. I got the motor started after about 15 minutes of trying and it ran well. Water was shooting out of the telltale like it should, idle sounded right, overall everything look good. After steady running for 5-10 minutes the overheat horn sounded (constant tone) so I shut the motor down. I waited a few minutes and when I turned the ignition key the alarm sounded again- not the quick beep but the steady tone. Any ideas? If the engine was overheating the alarm should not sound just by turning the key.
 

tnduc

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Yes, I went back out today and turned the key and got the standard short chirp so it looks like it was overheating. There was a good stream coming out of the telltale so where else do I need to check?
 

tnduc

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Thanks- I will check the thermostats next.
 

emdsapmgr

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A strong telltale only tells you that the pump is getting water to the powerhead. It does not tell you that it's circulating (and exiting the powerhead into the midsection.)
If one/both stats are stuck shut it will surely overheat.
 

tnduc

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I got out the service manual and took off the engine cover to get figure out where the thermostats are located While poking around I noticed a small pool of oil underneath the motor which tells me I may have something else going on, too. Thoughts on what other problem I may have?
 

ondarvr

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A small pool of oil isn't uncommon and normally means nothing. But you should check for fuel leaks, or leaks in the oiling system if it has one.
 
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tnduc

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Thanks. Now a simpler question: I am having difficulty locating the covers where the thermostats are. I have a service manual that shows how to disassemble and reassemble but not exactly where they are.
 

racerone

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Look where the 2 hoses come out and go to the bottom of cylinder heads.
 

emdsapmgr

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Those two hoses connect to the thermostat housing. Why not go to the factory parts diagram website and download a hard copy so you can work on it?
epc.brp.com
 

tnduc

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Those two hoses connect to the thermostat housing. Why not go to the factory parts diagram website and download a hard copy so you can work on it?
epc.brp.com

Got it, thanks. I ordered the parts so next weekend I will do the install.
 

tnduc

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I got my replacement thermostat set and proceeded with doing the replacement. I got out the service manual and see what I need to do-which seems straight forward. The center bolt came out easy enough, but the side bolts don't seem like they have enough clearance between the bottom engine cover to come out. Is there a specific trick to getting them out? Is there anyway to drop the cover without moving the powerhead?
 

emdsapmgr

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The flat rate for changing the stats included removing the powerhead. 2.0 hours. Most of us don't, and most mechanics don't either. You should be able to repair this yourself without removing it-since the engine has a flatback exhaust cover. It's the bubble back ones that are the stinkers. 3.5 hours. Most techs don't remove the powerhead on them either.
 
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