I installed a new impeller/water pump in a 9.9 merc,looking down the shaft in a clockwise direction..it will not pump water out the discharge tube, there is no obstruction in the discharge tube,so i thought maybe the thermostat was stuck shut,so i took it out sprayed some deep creep on it and got it loosened up,but it prolly needs replaced anyway, but i left it out...still no water being discharged. My question is,will it pump water without the thermostat in place or does it have to be in to build pressure?
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Thermostat Question
- Thread starter nc dawg
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Johny25
Well-known member
The peehole is usually always before the thermostat so it has nothing to do with it blocking the water flow out the peehole. We need more info to help though.....like year of the merc. And your info is a little vague? Looking down the shaft of......??? Did you mean copper water tube?
Was there a key on the impeller shaft and did you get it back in correctly?
Was there a key on the impeller shaft and did you get it back in correctly?
Tin Yachtsman
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I would think it would pump water through the tube without the thermostat. That's not something you want to do long term, though. I'm wondering if you installed the impeller key correctly? Are you using muffs or do you have the prop in a barrel?
Pee tube plugged. #-o
fender66
Well-known member
I'm with the others and think it might be the key not engaged in the impeller.
As for the water NOT going through the thermostat before the pee hole.....I disagree. (at least on my bigger Merc 225)
Last fall I put my boat in and noticed it wasn't peeing well...then it stopped. Pulled it back on the trailer and ran it up to a mechanic to get a new impeller. He told me that the water temps were so cold that the thermostats (both of them) were not opened yet and it wouldn't pee well until they were open.
I felt really stupid, but learned a good lesson.
As for the water NOT going through the thermostat before the pee hole.....I disagree. (at least on my bigger Merc 225)
Last fall I put my boat in and noticed it wasn't peeing well...then it stopped. Pulled it back on the trailer and ran it up to a mechanic to get a new impeller. He told me that the water temps were so cold that the thermostats (both of them) were not opened yet and it wouldn't pee well until they were open.
I felt really stupid, but learned a good lesson.
Thanks guys for the info..the discharge is after the stat,it is a 1991,lookin down the driveshaft and with the foot in my lap and turning the driveshaft and impeller
clockwise while putting the impeller into the pump housing.also have it in a barrel cause the pick-up is on the bottom of the cavation plate right behind the anode block. Could it be possible to completely miss the tube inside? idk
clockwise while putting the impeller into the pump housing.also have it in a barrel cause the pick-up is on the bottom of the cavation plate right behind the anode block. Could it be possible to completely miss the tube inside? idk
fender66
Well-known member
nc dawg said:
It is possible that the tube is not connected at the bottom. I've heard of that before. Just slips out of place when reassembling. I'm not an expert on this, but have heard of it.
did you try putting the thermostat in a pan of water and boiling it to see if the thermostat is still working?
look in your service manual and it should tell ya at what temp. it will open up at.
i do know that just cuz its not pissing water does not mean your waterpump is not working, the pee holes were first introduced by merc if im not mistaken cuz customers wanted a way to verify the pump was working, then everybody else followed suit.
start your motor and let it idle for 5 mins or so and if you cant hold your hand on the crankcase cover for 5-6 seconds minimum
there is a problem with the pump,impeller or thermostat...
look in your service manual and it should tell ya at what temp. it will open up at.
i do know that just cuz its not pissing water does not mean your waterpump is not working, the pee holes were first introduced by merc if im not mistaken cuz customers wanted a way to verify the pump was working, then everybody else followed suit.
start your motor and let it idle for 5 mins or so and if you cant hold your hand on the crankcase cover for 5-6 seconds minimum
there is a problem with the pump,impeller or thermostat...
You should be able to put your hand on the head & keep it there.If your water pump is not working it will not take 5 min or so to heat up.
Just because its peeing water doesn't always mean that motor is cooling.I always put my hand on head when checking a motor out to make sure its cooling.The older motors have small cooling ports that get plugged sometimes but still pump water. [-o<
crazymanme2 said:
very aware that it will pee sometimes even when its not cooling, guess i shoulda worded my post a lil better... was saying that the pee hole was just an assurance of water flowing through motor that mercury did to give customers peice of mind so to speak..
nomowork
Well-known member
I see that you've fixed the problem, but passing along something I learned on the web. I use an electric drill on the drive shaft after removing the lower unit from the motor and spin the drive shaft in a barrel of water to check for water coming out of the pickup tube to the power head. Just be careful of the direction you're spinning the driveshaft.
Johny25
Well-known member
fender66 said:
This may be true on larger outboards that it doesn't pee until the therm opens, but I still think they should have a bypass passage around the thermostat to allow some water, even a trickle to come out of the telltale. That is why I believe the peehole/telltale was put on motors, to show water was flowing. I am not familiar with the plumbing on Mercs but it doesn't make sense to me that a bad thermostat could make it not pee at all out of the telltale? But then again I have been wrong many times before
