Oily plugs. 1993 115 mariner 2 stroke

hawkster

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Jul 13, 2010
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Can you run the oil pump output back into the resivour and connect a aux. fuel tank with mixed fuel to check if my motor runs better and does not foul the plugs? I want to determine if the oil/gas mixing system is functioning properly. I've checked the linkage on the oil pump and it is set as noted in the manual.
 

Bravo

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May 28, 2010
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Re: Oily plugs. 1993 115 mariner 2 stroke

I can only offer an opinion to this, but I've "heard" that oil injected style motors don't really like this due to the engines inject the ammount of oil as needed, vs. the premix will be a set ammount of oil all the time. Does that make sense? Will it hurt it? Very doubtful IMO. I can't remember any of my past 2 strokes not having somewhat oily plugs though. Are we talking dripping off the plug oily, or just some residue? I love the 2 strokers... nothing like the smell first thing in the morning, LOL!
 

hawkster

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Re: Oily plugs. 1993 115 mariner 2 stroke

The plugs are very wet and it feels like oil when rubbed between your fingers. The color of the plugs are black like carbon. The plugs were just replaced and about 40 gallons of gas was used before they fouled out. I'm using NGK #BP8H-N-10 set @.040. Can dirty carbs cause this problem? I did the decarb proceedure using seafoam and the top end was better but still has issues with acceleration and fouling the plugs. I laso found some deposits in the accel pump and # 4 accel injector was stuck open. I cleaned the accel pump and made sure the check valves were seating on the # 3&4injectors. Any information would be greatly appreciated.
 

achris

More fish than mountain goat
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May 19, 2004
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27,468
Re: Oily plugs. 1993 115 mariner 2 stroke

If everything is set right and the engine seems to be running ok, then may I suggest you're using crappy oil....

And NO, oils ain't oils.... There are huge differences in the different brands...

Chris..........
 

hawkster

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Re: Oily plugs. 1993 115 mariner 2 stroke

I'm working on this for my little sister. I drained the oil resivour and put Quicksilver premium 2 cycle oil in it. Should I now change the plugs again? After I cleaned the accel pump and injectors it doesn't want to idle now either but the plugs do look wet and very oily. Does the gas and oil get mixed just before the fuel pump? If so what can cause a unbalance between the oil and gas mixture before it hits the carbs? Thanks for the help.
 

Dave1027

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May 25, 2010
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Re: Oily plugs. 1993 115 mariner 2 stroke

Yes, you can run the oil pump output back to the tank and use a premix. That's basically how the manual tells how to check the oil pump's output.

A better method is to do what I do. I monitor closely how much oil my motor uses compared to gasoline. I put indicator marks on the side of my oil tank for this purpose.
 

hawkster

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Jul 13, 2010
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Re: Oily plugs. 1993 115 mariner 2 stroke

Thanks I'll give the premix approach a try and see what happens. Thanks for all the good info guys.
 
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