2 cycle gas-oil mix

I know this has been covered, but due to the heartbreak of CRS, I'm not sure what the consensus was.

I've got a Stihl 031AV chain saw, circa 1973, book says mix 16:1, latest Stihl 2 cycle oil says 50:1, Stihl dealer (and the denizens of this board, IIRC) said go with the oil label. I've been mixing it a little richer than that, just to be on the safe side.

Picked up a 1954 Johnson "Sea Horse" 5.5 HP outboard motor for my small lake boat (remember the neat light metallic green color? She's a beauty, and its a shame to call it used). Manual (yeah, I got one) says 16:1. I'm thinking more like 24 or 30 to 1, with modern oil technology. I'd prefer not to be enveloped by a blue cloud, as I weave among the pedal-powered kayaks of the tree huggers.

What say the gurus here assembled?

I also have CRS. But I would go with the book. Most of the ones I have worked on. Have the mixture on the gas cap.I have learned that to much oil and you get a blue haze in the shop.

As you have stated two stroke lube oil has changed from 16:1 non detergent motor oil to today"s products. Some manufactures offer up to four different products. A dedicated outboard oil mixed 32:1 can"t do any harm and will keep the skeeter away.

My 75 Evinrude 85hp, that I bought used in 93, called for 25 to 1. I ran it 40 to 1 for 15 years (50 to 1 when I bought it premixed at the pump {Lake Cumberlin}) with no problem at all.

Make sure you use oil for outboard motors. It is different than regular 2 stroke oil. Has something to do with air cooled vs water cooled engines. I think it keeps the plug from fouling because a boat motor runs cooler.

I run stihl oil mix in everything. Mix it 2.5 gal at a time with the premeasured bottles. I used to have a lawn service and we would rack up a lot of hours on our 2 stroke stuff. I still have one of our older backpack blowers that I'm sure has several thousand hours on it. Never had an engine failure. I'd mix it like the bottle calls for and not worry one bit.

I ran '50's OB engines at a quart to 6 gallons and when I moved up to '70's engines (Merc, both OMC's and Chry) went to a pint to 6 gallons for outboards. On chain saws and weed eaters, I buy the Stihl syn oil with stabilizers and mix per directions which is the same 50:1 ratio as most later model OB's running TCW certified oil which is up to the III iteration currently. I too have read about different oils for the different types of service and either heat or rpm's apparently makes the difference. I like using the CS oil in my CS and WE as it is already prepared for long storage and works great.

Buttttttt super market shelves have long rows of different brands and oil types for sale so all our whims can get answered as it seems we all have a different opinion/sweet spot, when it comes to lube.

My 2c,
Mark

Thanks, John, I didn't realize there was a difference. Kind of new to the outboard motor thing- but grandkids (and their dads) want to go fishing, so had to get a big enough boat to accomplish it.

Going to Cabellas today anyhow, so will get the right stuff.

And thanks to all who posted.

I'm wondering what book you have that states 16 to 1? I worked for Stihl dealers back to the 60s and probably have every version owner's and tech manual Sthil ever printed for the 030 and 031 - along with all the other post-WWII saws. All state a 25 to 1 ratio if using SAE 30W motor oil or 40 to 1 ratio if using "special" Stihl two-stroke-cycle oil.

The newer richer mixes (less oil/more gas) have nothing to do with making your saw run better or last longer. It's all about emissions. So, newer saws have to be built with better materials to sustain less lube ratio. More oil in the gas still gives better protection for any saw. If it calls for 50 to 1, it will get better protection with 30-1 and even better yet with 20-1. It's not arguable as I see it. Many tests have proved it. More oil equals less metal wear. I run 20 - 1 in everything. This way I've got one mix that fits every two-stroke-cycle engine I own regardless if built in 1950 or 2012. The ONLY downside to using more oil is - you might have to open up the main jet a bit due to a leaner mixture and a spark arrestor screen might plug up faster. Stihl does not make any of their own "special" oils. I tend to use Ammsoil Dominator synthetic because it's specifically rated for air-coolded HD use and it's easy to find in quart or gallon bottles. I'm sure there are plenty of other good oils but I refuse to buy those rip-off little bottle. The prepacked premix is even more of a joke. Two-stroke-oil, unlike engine oil, is rarely tested and certified to meet specs. So, to a large degree, you have to be trusting in certain brand names and "in-house" testing.

I've run 20-1 in many of my older-then-40 years Stihls, along with my new Dolmars, Efcos, and Echos. NO problems and I see it as good insurance.

You can use too much oil in the mixture, causing a leaner mixture. Leaner causes a higher egt. Higher egt causes scored cylinders, burned pistons, siezed engine. More oil isn't better for the engine.

I have a 1957 5.5 Johnson. It is the brown and white one. It always used to be 16 to 1 but last I used it I mixed it about 32 to 1. My dad bought it new, I bought it from mom when dad passed away. Used it for many years but it now just sits in the corner. Actually, the last time I used it because my 15 horse shelled on me. I broke the spring loaded shock mechanism on the drive shaft. As they were longer available, and also Johnson went to a solid shaft I had it welded up solid. Did that to my former boss's 7.5 evinrude also. Trolled many, many hours with that little motor. Now I use an electric for slow mooching along, If and when I ever get fishing. It gets to be a lot of work now days.

Until recently used 50-1 oil in a 32-1 ratio because most ran thru the Homelite chainsaw which had that recommendation. The Homelite has a bunch of hours; now not often used and has been replaced with newer Poulan saws. String trimmers also recommend a higher ratio. So went with 40-1. The Homelite runs fine and everything spews less obnoxious smoke. But not willing to tempt fate and try 50-1.

Right you are, as usual, LJD- dug out the book, and it said 25:1. Guess I'll go with about that ratio on the outboard, too. Got Marine 2 cycle oil at Cabellas today. Outboard will be treated very gently, mostly trolling. Going to try my electric trolling motor too, but its a 14' fiberglass boat (1962 Scott), pretty heavy, and I don't know how well (or how long) the electric will push it.

Why don't you stick to the 16:1 and if shrouded in a cloud of smoke, raise it to 20:1 up, up, until you are satisfied. In the meantime save your money.
Do you really know if the modern oils are better for the machine.

(quoted from post at 22:16:10 04/14/12) Why don't you stick to the 16:1 and if shrouded in a cloud of smoke, raise it to 20:1 up, up, until you are satisfied. In the meantime save your money.
Do you really know if the modern oils are better for the machine.

Click to expand...

ll have overlooked the engineering design changes that may provide for a better scavenging of the oil & routing to bearings (differing bearings) than in the past............it isn't at all just better lubricants!
For me, I go with the original manufacturer recommendations, not some "current day" opinion or oil salesman's rec.
Still use 3/4 of a pint in 1 gallon in my 1960 Homelite, just like it says on the tank cap (10:1) and after 50 years it still cuts the wood! Good luck to those who cut the mfgrs rec!

I bought a new Echo trimmer Friday and the manual says to use Echo oil(no surprise there)at 50 to 1, and use 50 to 1 in all older Echo 2 strokes regardless of what was listed before. And yes outboards take a different spec oil.

Mike
I have an 1955 5.5hp Johnson. Great little motor!
I too was worried about the cloud of smoke, So I inquired on the Antique Outboard Motor Collectors club web site.
They reccomended staying with the 16/1 ratio
Because the motor has bronze bushings instead of
needle bearings.
Try a synthetic oil rated "TCW-3". It smokes less and it is enviromentally friendly.
Remember Oil is cheap insurance.
I'll post the link to the Outboard collectors
club site. If You have one old outboard, You'll
probabally get more. They're addictive!!!
I'm up to 31 motors now.
Good Luck with Your motor.
Steve A W
Outboard collectors club

Thnks for the post, and the link. I went to it and you're right, it could become addictive- but I've got too many other "addictions" laying around here, waiting to be fixed!

I did get the TCW-3, but the bad new is, I guess I should have got a bigger jug.

Sorry but some old outboards are not allowed on lakes anymore due to pollution requirements. Might check first. Dave