1990 mariner 8hp not pumping water thermostat?

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jy951

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I recently acquired what I believe is a mariner 1990 8hp. I put it in a tub of water and ran it briefly and shut it off when no water was seen coming out the taletell. So I figured the impeller was bad or a blockage. Does this have a thermostat? I tried blowing in the water outlet tube at the back of the block and could now force any air through it. Thanks.
 
Without the the serial # or exact model it's hard to say whether it has a thermostat or not, but a 1990 engine most likely does. You might also want to try running a small piece of soft wire up the telltale hole/tube a little ways to make sure one of those little wasp (dirt dobber as we call them) hasn't packed the tube with dirt.
 
It takes 2 seconds to take off the cowl and pull off the hose. Thats the only surefire way to completely clear the blockage if that is the case. For added measure, it wouldn't hurt to pop off the thermostat housing/water outlet and make sure that elbow is clear of debris.
 
I pulled the rubber tube off and I could blow air through it without issue. Any idea How long should the motor run before the thermostat opens and water comes out the tell take? Should I just wait until the powerhead gets warm? Or hot?
 
I've got a 96 Mariner 25hp and mine pee's immediately. I'd pop out the thermostat and throw it in a pot of boiling water and see if it opens. That would be better than warming the engine with no water cooling it.
 
I don't duck hunt or use my motor in the winter any more so I just removed my thermostat and it works fantastic and pees instantly (84 Mariner 25hp). I also don't have to worry that the thermostat might fail on me while I'm out in my boat now.
 
I pulled the lower unit off and the impeller looked good. The rubber boot that connected the water pump housing to the water tube was out of place slight and torn. I ran a clothes hanger up the water tube to try and loosen the obstruction with no success. I opened the thermostat housing and noticed there was no thermostat. I then discovered the blockage was right at the exit nipple of the thermostat housing. I just need that rubber piece that connects the water pump housing to the tube and I should be good. I appreciate all the input. Thanks.
 

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