2 stroke oil go bad????

[mudflat]

I'm repairing a 1987 Mercury 70hp. with auto mixing and the motor has set up for about 5yrs before I bought it. Should I drain the oil that is in the tank on the engine or does it not go bad?

 

[ondarvr]

Re: 2 stroke oil go bad????

Drain and clean it, sludge can build up plug the lines and pump.

 

[kenmyfam]

Re: 2 stroke oil go bad????

Welcome to iboats.
It may well be fine but for peace of mind I would clean the system out and start again.

 

[cougar1985]

Re: 2 stroke oil go bad????

that oil can go bad is unusual,think of it ,oil itself is millions of years old!could the additives seperate?possibly,so shake it up !

 

[5150abf]

Re: 2 stroke oil go bad????

Oil is cheap, a rebuild not so much, get rid of it.

 

[dingbat]

Re: 2 stroke oil go bad????

I drain and clean my oil tank every year. Usally find condensation in the bottom.

No way would I use oil that sat in a tank for 5 years. Not worth risking a high dollor motor over $20 in oil.

 

[rodbolt]

Re: 2 stroke oil go bad????

is this engine actually oil injected or does it have a stand alone part called auto blend?
if it says auto blend and is between the oil tank and the engine scrap it.
there is a reason we renamed auto blend to auto blow.

 

[ondarvr]

Re: 2 stroke oil go bad????

that oil can go bad is unusual,think of it ,oil itself is millions of years old!could the additives seperate?possibly,so shake it up !

As oil ages it will start to separate, but it will also change. There many additives that go into making oil, chemical reactions start as soon as they get mixed together, for a period of time everything will still be in spec and work OK, but over time they may break down and form other compounds or become ineffective. Sometimes they will even start to solidify or gel.

For a couple of bucks I can't see taking the risk.

 

[mudflat]

Re: 2 stroke oil go bad????

Thanks everyone for the feedback. I will play it safe and drain all the lines and tank then see what happens.