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Why are There Different Two-Stroke Oil Mix Ratios for Chainsaw Oil

Why are There Different Two-Stroke Oil Mix Ratios for Chainsaw Oil

Swamp mix.

That’s what you call a concoction of two-stroke oil and gas that’s been slopped together with no measuring tools and no regard for engine protection. Your chainsaw or string trimmer could be running on a 50:1 mix. Could be 72:1. Could be 147:1. There’s no telling.

I often made swamp mix back in the day. Like other adherents to the dark art of mixing foul-smelling liquids in a dimly lit shed, I did it for a couple reasons: 1) I didn’t have clearly marked measuring containers at the ready, and 2) even if I had, I wouldn’t have felt like playing chemist with my chainsaw when I’d rather be cutting brush.

I never blew up a saw doing this. But, then again, I’m not a professional logger, so I didn’t cut often.

Some people don’t like mixing two-stroke fuel/oil because it’s a mess. Some hate it because math makes their brain hurt.

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What is a two-stroke mix ratio?

The math isn’t that tough to understand. Say your chainsaw manufacturer recommends a 50:1 fuel/oil mix. This simply means you need 50 parts of gas to one part two-stroke oil. Two-stroke engines derive lubrication from the oil mixed directly into the gasoline, unlike your car engine, which lubricates itself with oil housed in an oil sump and circulated by an oil pump.

Complicating things, some equipment manufacturers recommend different mix ratios. While most modern trimmers, chainsaws, leaf blowers and the like call for 50:1, some older equipment recommends 32:1. If you have multiple pieces of equipment with different mix ratios, you have to mix and store multiple cans of fuel. That’s not only a hassle, it’s a situation begging for problems when you accidentally dump 50:1 in your saw that takes 32:1.

This scenario likely isn’t a problem for landscapers, loggers and other professionals who replace their equipment often due to heavy use. But plenty of homeowners still use older equipment that calls for a richer fuel mixture.

Life would be much easier if every manufacturer recommended the same mix ratio, right?

They don’t. But we do.

AMSOIL SABER Professional Synthetic 2-Stroke Oil is tested and proven at any mix ratio up to 100:1. That means you can mix one can of fuel and use it in all your two-stroke equipment. Done. Problem solved. If you want to use 50:1, use that. Or 80:1. For best value, use 100:1. You could mix at 71:1 if you want. It’s up to you.

And, to eliminate the hassles of mixing fuel, we offer bottle sizes matched to certain sizes of gas cans. For example, to mix AMSOIL SABER Professional at 50:1 in a 2.5-gallon gas can, just use an entire 6.4-oz. bottle. Use half the bottle for a 100:1 mix ratio.

That’s the ratio I now use in my chainsaw. As the piston images show, SABER Professional mixed at 100:1 outperforms other two-stroke oils at 50:1, fighting power-robbing deposits and maintaining operability.

AMSOIL SABER Professional mixed at 100:1 delivers better protection against power-robbing deposits than other oils mixed at 50:1.

With SABER Professional you spend less on oil, get better protection and eliminate hassle when mixing fuel. And you never have to make swamp mix again.

Saber Pro 100:1 is in stock at Sioux Falls, Stan Houston’s location

Should I Switch to a Lighter Viscosity Oil in Winter?

Generally with todays vehicles it’s not an issue but you should check the particular recommendations in the owners manual

Motorists sometimes ask if they should use a lighter viscosity of motor oil once winter arrives.

Yes – provided your vehicle manufacturer allows it. 

Run out to your vehicle and fish the owner’s manual from the glove box. Or open a digital copy on your phone.

Somewhere in the back you should find the motor oil recommendations. Many vehicles, particularly domestic, call for a lone viscosity of motor oil. It’s likely 5W-20 or 5W-30. That’s what you’re supposed to use all the time. Doesn’t matter if it’s -20ºF (-29ºC) or 100ºF (38ºC) outside. The engine was designed and manufactured to operate most efficiently using that particular viscosity of motor oil.

But some vehicle manufacturers – often foreign – recommend different motor oil viscosities depending on ambient temperature. You may find a chart in the owner’s manual like the one below that shows which viscosity you can use depending on the temperature. The manufacturer typically recommends a lighter viscosity when the temperature drops during the winter.

Typical viscosity temperature use chart in car's owners manual

Your vehicle owner’s manual may contain a viscosity chart like this one.

In this case, we recommend using the lightest recommended viscosity during the winter.

Why?

Two reasons:

  • Maximum wear protection at startup
  • Easier cold starts

To understand, you have to understand motor oil viscosity. If you’ve navigated to this page after a Google search, you probably know something about viscosity already. But a little refresher can’t hurt. (Check out this post for a detailed explanation of viscosity.)

Viscosity refers to the oil’s resistance to flow and is its most important property. The lower the oil’s viscosity, the more readily it flows at cold winter temperatures. Of course, the opposite is true – the higher the oil’s viscosity, the more slowly it flows when cold. That means an 0W-20 oil will flow better when it’s cold than a 10W-30.

Dub-ya

Which brings me to my next important point.

The oil’s “W” viscosity describes its characteristics when it’s cold. And by “cold” we mean 40ºC (104ºF). The second number (e.g. the “30” in “5W-30”) describes the oil’s characteristics once your engine reaches normal operating temperature, or 100ºC (212ºF).

Engineers agree that most engine wear occurs at startup. One reason is because gravity pulls much of the oil into the sump as the vehicle sits overnight.

When you start the vehicle the next morning – even if it’s not that cold outside – a few critical moments pass before the motor oil travels through the oil pump and navigates the narrow oil passages to reach components throughout the engine. It’s during those moments that accelerated wear can take place.

As such, it’s beneficial to use an oil that flows readily at startup to reach engine components as quickly as possible.

Since lower-viscosity oils flow more readily, they provide better cold-weather startup protection compared to higher-viscosity oils.

On a side topic with AMSOIL if your vehicle calls for 5W-20 or 0W-20 both can be seen as interchangeable with the superior synthetic base oils used. Neither one make a cotton picken bit of difference unless we are at -45 all week, then the 0W-20 may be a little better.

From South Dakota to Texas many of our

Crank it up

Lower-viscosity oils also provide less crankshaft resistance as the engine turns over. When the temperature plummets below zero, the motor oil can thicken so much that it prevents the crankshaft from spinning fast enough to start the engine. This is particularly a problem with conventional oils since they contain waxes that thicken in the cold. Synthetic motor oil, in contrast, doesn’t contain waxes and, therefore, provides easier cold starts.

Check out the video to see for yourself.

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Along the same lines, oil that provides less resistance to moving engine parts also maximizes fuel economy. That’s the primary reason automakers are trending toward lighter viscosity oils in their new vehicles.

A word of caution…

It’s important to note that using a higher-viscosity oil does have its benefits, too. Higher viscosity oils tend to provide improved wear protection since they promote formation of a thicker fluid film on engine parts. They’re also more resilient to oil consumption than lighter viscosities.

Bottom Line: Switch to the lightest viscosity oil your vehicle manufacturer recommends in the winter. Doing so maximizes wear protection at startup while improving cold-weather starts.

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