Violent Stalls and White Grease Leak

[wippel]

I have a 15+ years old Mercury 7.5 HP. When I initially start it after a day or two, a whole bunch of small clumps of white grease float on the water. I have checked the lower unit and the grease is clear (not the typical milkshake look of a lower unit leak). As well, and I don't know if it is related, once the motor warms up, it won't idle at all, in fact it won't even run at an engine speed close to idle, stalling very violently as I begin to slow down. Any ideas ?

 

[jim dozier]

Re: Violent Stalls and White Grease Leak

Pull the plug(s) and check for evidence of water in the cylinders. I think the "white gease" is emulsified water and outboard oil coming out of the exhaust which may indicate (along with the poor idleing) a water leak such as a leaking head gasket. Also do a compression test. Report the numbers here.

 

[greasemonkeyozi]

Re: Violent Stalls and White Grease Leak

When you run a compression test, your numbers, or PSI should have no more than a 10 PSI difference in each cylinder. If there is, you will automaticlly know that there is a problem and that a major motor rebuild is at hand, that will also fix your white grease chunk problem... Are you good with motors?

 

[CRANKIE]

Re: Violent Stalls and White Grease Leak

I HAD A PROBLEM WITH A 50HP THAT SOUNDS LIKE YOURS. IT WAS A BAD FUEL PUMP. FUEL WAS PULLED IN, MIXED WITH WATER AND PUMPED OUT WITH EXHAUST. ALSO POOR RUNNING WHEN HOT. YOUR ENG DOES NOT HAVE A FUEL PUMP AND TRANSFER PORT LIKE MINE (IT"S ON THE SIDE OF THE CARB) BUT UNBURNT FUEL FROM A DEAD CYLINDER WILL GIVE YOU MILKY WHITE LUMPS OUT WITH EXHAUST. KEEP THIS IN MIND AS YOU DIAGNOSE YOU PROBLEM.

 

[wippel]

Re: Violent Stalls and White Grease Leak

I did a compression test, although I'm not entirely sure that I did it correctly. I pulled the plugs, for each cylinder I hooked up the compression tester, pulled that starter cord about 10 times and took a reading. The motor was however not warm as I don't have a test tank, and would need to take it to the lake to run it warm. <br /><br />I did the test 3 times on each cylinder and recorded readings ranging from 82-85 PSI on one and 85-88 PSI on the other. <br /><br />Doesn't seem like a significant difference between cyclinders, but, then I'm no expert. That's where you guys come in. <br /><br />One reply mentioned looking for evidence of water in the cylinders. What would I look for? The plugs looked perfect, but, that may not mean anything.<br /><br />Any help would be great.

 

[The Marine Doctor]

Re: Violent Stalls and White Grease Leak

The easiest and cheapest way to find if there is water getting into the block is through the exhaust plate on the port side of the engine. It is held on with 7/16 bolts.<br /><br />This is likely where water would be getting in anyway. Pull them off and have a look.<br /><br />The new gaskets are cheap.<br /><br />TMD

 

[wippel]

Re: Violent Stalls and White Grease Leak

Are you referring to what my manual is calling the 'Outer Exhaust Cover' and 'Inner Exhaust Manifold' which has 2 gaskets, one between the two and another between the Inner Exhaust Manifold and the block ?<br /><br />Looks easy enough to have a peak. I'm curious how water even gets to those? Once I'm in there, what am I looking for? I haven't run the engine in quite some time (didn't want to hurt it more), so I suspect I won't see any water in there. Am I just looking for bad gaskets?

 

[The Marine Doctor]

Re: Violent Stalls and White Grease Leak

Yes..those are the covers. Water has to circulate up there to cool the exhaust housing.<br /><br />TMD