1997 Mercury 150 EFI

[TN Fat Guy]

My motor quit on me and I took it to the local boat repair shop and there was oil in the fuel reservoir and he said I would be better off mixing my own fuel and oil. Oil comes out of the oil reservoir on the motor when you take the cap off. Is this normal? Could this be why so much oil was in the fuel reservoir that the motor quit?

 

[Jeff_G]

Re: 1997 Mercury 150 EFI

You need a new shop.
Fuel is pumped to the vapor separator tank, VST. There it is mixed with oil from the oil pump, sent then to the injectors. So there better be fuel/oil mix in the VST.
The oil resevoir is kept full at all times via a pressurized system that gets oil from the remote tank and sends it to the on engine tank. If the engine was recently run yes oil will overflow when the cap is taken off. There should be no air in the oil tank.
Whether you take out the oil system is up to you. You can pre-mix your gas and oil. You will burn more oil and have some additional smoke, but it will be in there. If you decide this then you will need a special Mercury block off plate with a couple of O rings, Under $10 at most dealers. You will need to remove all the oil components and block the pulse fitting.
post back if you want to go this route.
If the oil system is running fine and the oil warning module is OK then you may want to leave things as is.

 

[Faztbullet]

Re: 1997 Mercury 150 EFI

I have seen this several times that the VST fills with to much oil.The problem is the bleed hole in pulse fitting is stopped up or stuck over pressurizing oil tank in boat .This then pushes oil thru oil pump into Vst tank causing hard or no starting and when it starts it smokes awful.

 

[Jeff_G]

Re: 1997 Mercury 150 EFI

I have seen this several times that the VST fills with to much oil.The problem is the bleed hole in pulse fitting is stopped up or stuck over pressurizing oil tank in boat .This then pushes oil thru oil pump into Vst tank causing hard or no starting and when it starts it smokes awful.

There you go! I wasn't even thinking about too much oil in the VST, just an oil fuel mixture in the VST which would be normal. I stand corrected, and agree wholeheartly with Faztbullet.

 

[TN Fat Guy]

Re: 1997 Mercury 150 EFI

Thanks. That was the problem, too much oil so it wouldn't start. I took it out on the lake today and it ran as good as new, so I think I will leave it alone for the time being. Thanks for the replies.