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Oil leak Mercury 125hp 2-stroke

TIMES TWO ON THIS POST!!!!

I own a 125 and They leak from the breather at the top of the tank when tilted full up!

Its leaking from around the oil filler cap. They all did it. Take the cowling off, fill the oil tank about 3/4 full and mark a line on the tank where the oil is with a sharpie with the engine in normal running position. Next, tilt the engine up until the oil just reaches the filler neck on the oil tank below the cap o ring. Next take a piece of white masking tape and place it between the stern bracket where your steering cable enters the bracket and the bracket that actually swivels up and down as you tilt the engine. Cut the tape at the joint and this will become your visual reference as to how far you can tilt engine without it leaking. When the two pieces of tape line up when your tilting up that's where you stop. It was a stupid design that leaked almost from brand new. I have twin 115 's that did this from day one. Now when you go to fill your oil tank back up, only fill to your reference mark on the side of the tank and you wont have any more leaks.[/QUOTE]
 
Jhanratt said:
TIMES TWO ON THIS POST!!!!

I own a 125 and They leak from the breather at the top of the tank when tilted full up!

Its leaking from around the oil filler cap. They all did it. Take the cowling off, fill the oil tank about 3/4 full and mark a line on the tank where the oil is with a sharpie with the engine in normal running position. Next, tilt the engine up until the oil just reaches the filler neck on the oil tank below the cap o ring. Next take a piece of white masking tape and place it between the stern bracket where your steering cable enters the bracket and the bracket that actually swivels up and down as you tilt the engine. Cut the tape at the joint and this will become your visual reference as to how far you can tilt engine without it leaking. When the two pieces of tape line up when your tilting up that's where you stop. It was a stupid design that leaked almost from brand new. I have twin 115 's that did this from day one. Now when you go to fill your oil tank back up, only fill to your reference mark on the side of the tank and you wont have any more leaks.
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[/QUOTE]
Mine leaks without tilting it up after being out driving. I have no traces of oil at the top of the oil tank.
 
I wish you the best of luck with it. My 150 HP mercury leaked constantly and everything under the cowl was oil covered until I started filling my oil tank half full. That was the end of my oil issues.
 
Jhanratt said:
I wish you the best of luck with it. My 150 HP mercury leaked constantly and everything under the cowl was oil covered until I started filling my oil tank half full. That was the end of my oil issues.
Click to expand...
But theres no oil as you see on the picture all over the engine like you describe?
 
My oil leak was from the top of the oil tank at the breather. It would leak slowly while tilted up. The oil would cling to everything from the wiring harnesses to the engine to the insulation on the inside of the cowl and the cowl gasket. Then when I ran the engine it would get warm the oil would get thin and start running out everywhere. Mostly ending up in my motor well. Once I figured out not to fill the tank past about half my problem stopped.

Good luck with it!
 
Jhanratt said:
http://www.marineengine.com/parts/m...25-4-cyl/0t980000-thru-0t999999-usa/fuel-pump

use the link above or enter your own serial number in the engine diagram link above navigate to fuel pump.
Looks right to me based on the parts diagram and based on an inspection of my own 125 HP.

Good luck.
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I did not have this problem nor have I ever changed this valve on my outboard.
My leak was from the air breather on the top of the tank or from the filler neck. My problem was solved by filling the tank no more than 1/2 - 3/4 full.
I was just trying to help. It looks like the valve discussed earlier the one is the same one in the image.

Jeff
 
Jhanratt said:
I did not have this problem nor have I ever changed this valve on my outboard.
My leak was from the air breather on the top of the tank or from the filler neck. My problem was solved by filling the tank no more than 1/2 - 3/4 full.
I was just trying to help. It looks like the valve discussed earlier the one is the same one in the image.

Jeff
Click to expand...

can I put my fuel hose that goes from my fixed tank to a bottle of fuel mixed with oil after I have changed the valve? This to remove all airbubbles in the system before I plug it back to my fixed tank.
What mixing ratio shall it be?
 
I personally would try to make the swap quickly without losing oil from the line.
If I was not successful and lost oil or introduced bubbles then I would hook the motor to a portable tank of 50:1 and idle it until all the bubbles are bled from the line.
I have never worked on the oil injection system of these outboards but I have worked on the injector systems on my snowmobiles.
You can drive the oil pump on a skidoo by running the pump on a cordless drill to remove bubbles.
Not saying that would it work on this system because I don't know what drives it.

The above is just my opinion!

Be careful! 2 strokes require oil at all times.

Good luck.
 
I gave you these instructions over a week ago as to what to do when you replace the valve...

Usually there is an excessive amount of oil in the engine when the valve goes bad and they smoke a lot when you start them. Yes, remove the spark plugs. Make sure you ground the coil leads; put the plugs back on the plug wire and make sure they touch the block to keep from harming the ignition system. Turn the key to start and turn the engine over for 5 seconds to make sure there is no residual oil in the engine. Also, since you are disturbing the oil system on the engine you may introduce air into it. When you start the engine for the first time after you replace the valve, make sure you start it on a remote tank with a 50-1 mixture of oil and gas so the engine is being lubricated while any potential air is bled through the oil injection system, 10 minutes should do it, then switch back to your normal fuel supply.
 
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