Pre mix

[Rebel SS]

I just was reading in one of my chain saw manuals.  It is a Stihl.  It said of course to use their oil but if you don't buy quality chain saw or air cooled 2 stroke oil.  The also said DO NOT USE Marine or water cooled 2 stroke oil in place of air cooled oil.  I know I used to do that all of the time and never had any problems.  I am much more careful now. 

Yup, that was one of the biggest issues on a certain auger column...
DON'T use marine oil in an air cooled engine; ie; ice auger, and vice versa.

A little snippet From an oil/engine builder company....

Think about this: the main difference between 2-cycle outboard engines and 2-cycle power equipment engines is how they're used. An outboard engine on a boat is typically accelerated to a particular RPM, which maintained until you've reached your destination. (Typically half the RPM of a chainsaw or concrete saw.) The engine on a 2-cycle chainsaw or concrete saw is constantly stopped and started, alternating between periods of idle and periods of redline RPM's, upwards of 14,000 RPM!

Another point to consider, is that outboard engines are typically water-cooled and have a constant flow of fresh coolant which is not recirculated. This means that overall engine temperature is much lower than that of an air-cooled 2-cycle engine found in a chainsaw.

Water-cooled outboard engines require a heavy oil to prevent piston scuffing. In addition, oils containing detergents should not be used in an outboard engine, as the detergents may form ash deposits in the cylinders and foul spark plugs. Since outboard engine oils don't include detergents found in 2-cycle outdoor power equipment oil, they require a high amount of dispersants, rust, and oxidation inhibitors to control deposits and rust.

Air-cooled 2-cycle oil for outdoor power equipment require less heavy oils, which can cause piston ring sticking and loss of power. Due to operating conditions and temperature, a high detergent formula is used, which provides deposit control under high temperature use, unlike outboard engine oil. High detergent oil provides necessary protection from high RPM, high engine temperature operation and engine damage.

As you can see, there is a major difference between outboard engine oil and 2-cycle oil for power equipment. By using outboard engine oil in your power equipment, you're only doing harmful damage to your engine. Always use an oil meeting the American Petroleum Institute (API) service classification TC, which is the best oil for 2-cycle, air-cooled engines. 

[LPS]

Very good article.  I accidently mixed my chain saw gas at 16-1.  I cut some tamarack and then thought about it.  One of those small bottles in a gallon actually is 16-1.  My chainsaw says 50-1.  So it is real rich.  Doesn't seem to smoke at all and runs good so big deal I guess... 

[mike89]

good info Reb, thanks!!

[Rebel SS]

Very good article.  I accidently mixed my chain saw gas at 16-1.  I cut some tamarack and then thought about it.  One of those small bottles in a gallon actually is 16-1.  My chainsaw says 50-1.  So it is real rich.  Doesn't seem to smoke at all and runs good so big deal I guess...

That won't hurt a thing, Barry. Might foul the plugs a tad at most. You can always add a qt of gas to it and still be fine.
The ones that always ran into issues were these guys that would run against the 50:1 ratio and go with 100:1, which many said you could do with a good synthetic oil. NOT. If yer manual says 50:1, ya run it 50:1, just my opinion.