View Full Version : Mercury m2 pump, drain plug ?

03-28-10, 12:41 PM
Mercury m2 210hp jetdrive pump. Ive read the howto's on changing the pump oil. I know there is a vent plug and drain/fill plug. My question is if the drain/fill plug is the same, after you drain the oil, and you pump new oil in, how do you keep the new oil from running out?

03-28-10, 01:15 PM
This is the thread my questions is based on


Im not understanding how the drain/fill plug is the same. If im pumping gear oil in there gravity is going to make it drain back out. Can somebody tell me what im missing?

03-28-10, 03:38 PM
I climbed under my boat and removed the drain/fill plug and also removed the vent plug. I have very little oil coming out. Maybe a few drops. I know this cant be good. How much oil is expected to some out? From what I've read I should be getting a liter or so. There is oil in the stator because I did change it. Does the boat need to be leveled in order for it to drain? Its on a slight incline. I can lower the jack to level it.

I took the boat out all last season. I never noticed any performance issues or issues with the pump. Boat planed out fine and i would get 55mph on flat water. I know that is typical of these boats.

Maybe no damage is done considering 90% of the time we would drive 1-2 miles out and swim and then drive back.

- BiRkS_
03-28-10, 04:05 PM
idealy the boat should be level. To fill the reservoir, fill from the fill hole and when oil starts to come out the top, put the vent screw in. (it helps to have another person helping you) make sure you keep constant pressure (as soon as the oil appears by the vent, dont stop the pressure, equalize it so the oil is just at the vent screw) when the vent screw is in, quickly take out the bottle or hose you are using and quickly insert the fill screw. you will loose a little oil, but not enough to be worried about. make sure you tighten both screws so they dont come out in the water. Wipe off all the oil, so you dont pollute the water.

03-28-10, 05:58 PM
Birks is right on on with how to fill the pump, as for no oil coming out I have found that is often the case. Not that there is no oil in the pump, but rather it is so thick it does not want to start to flow. Anytime I change the pump oil on my Utopia I use a blow gun hooked to my compressor to gently blow in the vent hole to help the old oil out. I can't stress enough though to be gentle with the air. You don't want to blow a seal out or you'll be pulling the power head to change it.

The pump hold just over 800ml.


03-28-10, 06:05 PM
I think that is the case is that it is too thick to come out on its own. Which tells me that it hasnt been changed in awhile. I was only able to get around 14oz in there. I pumped oil until it came out of the vent hole and then quickly plugged the vent hole and pumped some more. When i disconnected the bottle pump, oil burst out then I placed the plug in. So i know its full now.