Can motor oils (e.g. 20W50 or similar) be used instead of a 4 stroke mower oil ?

Question

Can motor oils (e.g. 20W50 or similar) be used instead of a 4 stroke mower oil ?

Answer 1

can it be used? .. yes... should it be used? ... NO.... If I checked my lawnmower and it was down a couple of ounces .. note I said ounces I would probably add  what ever 4 stroke motor oil I had on hand,.. just so I could finish the job... BUT I WOULD BE WORRIED,If I put in a QT of 20/50W.. Understand,  a car engine is also a 4- stroke motor, and it is water cooled .. unlike a typical lawnmower which is air-cooled.. The car engine endures extremes of temperatures.. ex: extreme cold.. and extreme heat, hence the versatility of multi-viscosity oil,.. such as 5-30W..(10-40. for diesel)  and 20-50Wsynthetic for high revving engines...THE BOTTOM LINE IS....IF YOU HAD TO ADD 20-50W  to finish a job go ahead.  But remember to change it when you get a chance... your lawnmower runs best on straight  30w API SERVICES SM/SL ( found on the label)

Answer 2

... yes they can  a 4 stroke mower engine is no different than say a 4 stroke motor bike engine ..they both work on the same principal and have an oil reservoir ...obviously you want to get the oil about the same viscosity ...some of your answers all ready received are by people who have never stripped or worked on an engine in their lives ...oil never passes anywhere near a carb  on a 4 stroke ..and Ive been mowing for fifty years ..and own a garage repair centre !

Answer 3

I am guessing you meant to say 2 stroke mower oil and are talking about oil fuel mixes.  For years and years there was no such thing as 2 stroke oil.  Straight 30W non- detergent engine oil was the only "two cycle oil" available.  However, it was mixed at an 8, 10, or 12 to one ratio depending on the engine specs.  You could still use it but you wouldn't like the smoke, plug fouling and carbon build up that you avoid with the 2 stroke oils of today.  

If you are talking about crankcase oil I believe most manufacturers recommend SAE 30w or 15W30.

Answer 4

NO, NO, NO, don't do it, you'll muck-up the carburetor

Answer 5

no,they have additives that should not be in the combustion chamber