Mercury 9.9 Water Pumps Intermittently

[CichlidMan]

Hey Guys! I recently purchased a new motor. It has been stored for about 6 years. It's a 99 9.9 Mercury with electric start. The problem is the water does not pump steady. It will pump then slow to a trickle, then pump again. I don't know much about boat motor's. The line that the water come's out of seem to be clear, as i stuck a piece of coat hanger up and was clear. Could this just be the thermostat opening and closing to pump as it is needed? I had the boat out last weekend for the first time.. Water is pretty cool on the lake as opposed to summer.. Any help would be appreciated. I do not want to cause any damage as this motor has been stored since 2005 and has under 30 hours use on it.

Ty

 

[will941s]

Re: Mercury 9.9 Water Pumps Intermittently

Your fine, I would replace it along with the t-stat- anyway just because it's been sitting, but it's doing what it's made to do. If you follow the pee tube it goes right to the t-stat housing. As the t-stat opens and closes, it pees and stops. If your running wide open, it'll pee the whole time due to the engine being hot. When you idle again it'll open and close.

 

[Barnacle_Bill]

Re: Mercury 9.9 Water Pumps Intermittently

If it has been sitting for 6 years you need to replace the impeller. They can dry rot sitting for a long time like that.

 

[cr2k]

Re: Mercury 9.9 Water Pumps Intermittently

Read my signature...

 

[CichlidMan]

Re: Mercury 9.9 Water Pumps Intermittently

Thanks for the fast response guys! I've been working and its been raining.. Heading to town today to get a book from the library and pick up a new impeller. Going to try that and hopefully it does the trick. Will post when I test it out to let u know. TY Chris

 

[CichlidMan]

Re: Mercury 9.9 Water Pumps Intermittently

Well I got the impeller changed with no problems.. Flushed and changed the bottom end oil. It's pumping water steady now, but it seams like it has a bit of air or something.. Going to change the water pump when I can afford to buy the upper and lower kits. Other than that the motor runs great. Had it out all weekend. Thanks for the help guys. Chris