mercury leaking 2 stroke oil

[amosh]

my v-200 1991 mercury is leaking oil. I replaced the gasget for the on motor reservoir cap, but its still doing it, so I think I got it traced back to the vent tube. is there anyway to stop this leakage or is it something that you live with on a direct injection engine like mine. don't think its hurting anything but its unsightly to walk around the back and have a blue puddle in the engine well. thanks for your help

 

[Texasmark]

Re: mercury leaking 2 stroke oil

No idea as to your engine but on my 90 I tilt my engine all the way up and check the height of the oil in the self contained reservoir that would just be at the level of the cap. Result is oil tank is about 2/3 full so I never fill it above that. Even with a new gasket, since doing that, no problems. Might work for you.

Mark

 

[Faztbullet]

Re: mercury leaking 2 stroke oil

Sounds like a cracked cap.....

 

[amosh]

Re: mercury leaking 2 stroke oil

mark, there is a remote reservoir, and an oil pump that takes it from there to the reservoir on the engine, so that you don't have to take off the cowling to fill it with oil, so I don't really have control as to filling it 2/3, but glad it worked on yours. would a cracked cap create pressure to push it out of the vent, or would my leak be localized to the cap. to me it looks like it is mostly coming out of the vent tube on the side, running down the control hoses and cables, and dripping into a puddle on the well of the boat. is there a way to check the cap other than visual inspection? I couldn't see a crack, but that doesn't mean its not

 

[sam am I]

Re: mercury leaking 2 stroke oil

my v-200 1991 mercury is leaking oil. I replaced the gasget for the on motor reservoir cap, but its still doing it, so I think I got it traced back to the vent tube.

If I understand correctly, you replaced the cap gasket but, the oil wasn't actually coming out from under or at the cap? You replaced the gasket thinking it would stop the leaking not knowing quite where the leak was actually at? But think it's at/coming out the vent tube, #6?



Sounds like the check value #7 is stuck open/bad if oil is coming out the end(#5) of the vent tube, the check valve there allows air in in the event the remote tank's oil supply hose gets pinched closed/blocked(it prevents a vacuum from forming and so allows the system to gravity feed oil properly) , nothing should be coming out of the tube.

If not coming directly out the end but, anywhere/somewhere in the hood....joints, fittings etc, tighten/replace all tie wraps/hose clamps and check/replace all hoses with cracks and hardening......especially the clear one merc installed for "seeing the oil" through.

There is about 2PSI to 3PSI normally(at idle'ish) on the oil side of that check valve and in both those oil tanks up to the oil pump's input when all is tightly sealed and properly running,

i.e., the contents are under pressure and oil will squirt out where ever it can and......You should have no oil leaks what so ever.......

 

[amosh]

Re: mercury leaking 2 stroke oil

I replaced the gasget at the cap because there was some seepage coming down the tank, as well as a puddle around the motor coming off the control cables. I replaced the gasget, wiped down the tank and all other residue I could, and ran the boat. still leaking, but no oil residue on the oil tank, so not the cap, but still puddle and oily below the vent. I did not know there was a check valve at that point in the system, so thanks for that diagram. I will replace that and see how it goes