Chain saw gas mixture

[Sammy in Kansas]

I just bought a couple chain saws at an auction and they are both running but I need to know the proper gas/oil mixtures ratio. first is a Jonsered and the other is a McCullogh. Thanks in advance for your help.
 

[MrJDMan80]

Both should be 50/1. When using a quality oil mix.
Tim
 

[wisbaker]

If they're really old they might be 20:1 it should say on the fuel cap or on a data plate. If not search the internet by make/model for an owner's manual or specifications sheet. Some will allow you to run 50:1 if you use synthetic two cycle oil, but that was a specification from 30 years ago. Just the brand name doesn't give enough information as the manufacturers changed their requirements over the years. They are probably 50:1. Find a manual it'll tell you what ratio and what type of oil to use as well as what chain oil to use and explain the user adjustments on it.
 

[Bret4207]

It really depends on the model and when they were made. Jonies for the last 25 years or so have been 50-1 engines. A Mac might need something more like 30-1 or richer depending on how old it is, or it might be a 40 or 50-1 machine.

FWIW- I have saws dating from the early 60's up. I tend to run about 40-1 in all of them with no problems. But you want good 2 cycle oil, not outboard oil and certainly not motor oil! The biggest reason the old engines used 16-1 or 20-1 was because the lubes were so poor back in the day. With a good 2 cycle oil, assuming the saw isn't worn out or has been abused, I think something in the 35 or 40-1 range will work for most saws. There will be exceptions that simply require a richer mix due to specific wear, design or conditions. IF the saw will run good at 50-1 then that's what I'd go with. Too much mix oil is almost as bad as not enough.
 

[Dusty MI]

Why not outboard motor oil ? Outboard motors were 2 cycle engines.

Dusty
 

[Jim in Ma.]

I read somewhere, Outboard oil is formulated for a water cooled engine.
 

[Butch(OH)]

Always a topic for disagreement but my two cents is buy a quality mixing oil made for air cooled engines and use it at the label ratio. Somebody asked about "outboard" oil and the answer is differant operating temps for water cooled engines. Some outboard oils meet the lessor or older air cooled engine specs but none of them meet the toughest newest specs for air cooled engines. Oil is cheap enough why take a chance is the question here? I personaly own 25 saws from brand new to antique and I run the same fuel mix in all of them, Stihl sythetic at 50-1. While I admit the antiques only get run enough to keep them limbered up it also doesnt take long for lubrication failures to show up either. My experiance from the pile of non-running saws, weed eaters, tillers etc that show up at my shop door tells me a person should worry about keeping his fuel mix fresh, proper storage preperation and his carb set right rather than what brand of oil or oil/fuel ratio he is using, other's experiance differs.
 

[Gary from Muleshoe]

You are obviously computer literate so why not google you question with make and model and get a sure answer?? Just a thought. Usually on here you five experts that don't agree on anything.
 

[RodinNS]

An old Mac will want 25:1 mix. The newer ones that are repainted Poulan's will work as well as they're going to work on 50:1. The Jonsered if it's made after 1980 should be fine at 50:1.
I'd also add that to use 50:1 ratio you NEED an oil like the Stihl synthetic or an oil of equivelant spec. All mixing oil is not created equal... That oil is actually made by Castrol and no doubt marketed by Husky and Jonsered as well.
Newer saws, particularly with spark arrestors and emission junk need the leaner ratio or else they plug up their exhausts if you use too much oil...

Rod
 

[Eldo case]

I use OPTI-2 in my all of my mixed up saws and weedeater of all ages and mixes. Don't have to worry about wrong mix or how old the fuel is. No trouble having had used for years.
 

[buickanddeere]

More oil is not always better.
Extra oil results in more combustion residue and lowers the fuel octane which makes detonation more likely.
Use 91 or better octane in a small high output air cooled engine. More engines have been ruined from detonation than from lack of lubrication.
 

[hintocw]

I only use Stilh synthetic oil (50>1 mix)in all of my 2-cycle engines, have been doing same for over the last 20 years with absolutely no problems.
 

[D beatty]

eldo case I to use OPTI-2 in all my 2 cycle engines with no problems for over 12 years. I like not having to mix a half dozen different mixtures. Engine have very little smoke and it doesn't stink like most of the other mixs.
 

[LJD]

A real US made McCulloch made into the 1980s (and not a later Asian saw) calls for a 20 to 1 mix with SAE 30W motor oil or 40 to 1 with air-cooled rated two-stroke-cycle oil..
Early Jonsereds circa. 1960s used 10 to 1 with SAE 50 motor oil. Later Jonsereds used 40 t0 1 with air-cooled rated two-stroke-cycle oil.

Just about any saw will do fine with that sort of mixing. I've got two dozen saws I use and all get 25 to mix with air-cooled rated two-stroke-cycle oil. I've been doing that for 50 years now and never burnt up an engine yet. That includes several new saws that call for 50 to 1. My 25 to 1 mix works just fine and it's cheap insurance. The reason for the low-ratio modern mixes is the EPA and has nothing to do with engine longevity. It has been proven over and over that even new engines last a bit longer with heavier mixes. Newer saws are built with more durable materials then many older saws because of the low oil mixes.

What Buick-Deere stated is almost 100% true. Yes, heavy mixes plug up spark arrestors (if you have them). Eventually they all plug anyway. Easy to clean or remove. And yes - more oil to a mix makes a saw run leaner since carburetors work by volume. More oil means less gas per cc. No problem as long as you can adjust the carb and open up the main jet a bit. The benefit of a heavier mix is it allows for mix-mistakes, allows use in older engines that call for 16 to 1 mix, and will help any engine - new or old last longer.
 

[MarkB_MI]

Until fairly recently, two-stroke oils for outboards and air-cooled power equipment were the same. That changed with the introduction of the TCW classifications (latest is TCW-3), which are specifically formulated for water-cooled engines. Sure, you can use TCW-3 in an air-cooled engine, but you're much better off using a JASO FD/ISO-L-EGD oil like Opti2.