Gas / Oil Mix Ratios

Discussion in 'Landscape Maintenance' started by FarmerCharlie, May 20, 2011.

  1. FarmerCharlie

    FarmerCharlie LawnSite Member
    Messages: 26

    Does anyone have a general recommendation for the gas/oil mixtures for various engines? The recommended oils and ratios vary from about 20:1 for my old 1950s era Elgin outboard through 40:1 for my Husky chain saw to 50:1 for my new Shindaiwa C4 trimmer. In the past I just settled on the 40:1 Husky oil for everything (except the old outboard), and I wonder if there is any strong reason to change from that.
  2. RAlmaroad

    RAlmaroad LawnSite Silver Member
    from SC
    Messages: 2,257

    Is missing something here? Each manufacturer of an engine has tested their product and has established which ratio of gas to oil to use. You should go by their recommendation else you could burn up your plug or engine piston or cylinder wall with too lean of a mixture. As to reasons each motor has a thickness of the critical heated parts which are tested as to air cooled fins, speed of engine, all sorts of variables which they know about. If you had 5 different machine; each requiring as stated in the manual to use a ratio then you'd need 5 different mixes--just label each one. Better yet, if you stay with one manufacturer such as Stihl then most of their engines would generally have the same mix. Remember way back in the 60's how those big cars with 454 carbed motors needed only super leaded octane gas to run? They would run on today's gas for the same reason. Sure they might spit and sputter but would run properly on their intended gas. I know very little about the workings of gas engines but am sure there are reason for the recommended ratio. Go by the manual.
  3. 32vld

    32vld LawnSite Gold Member
    Messages: 3,983

    You want a recommendation?

    Follow the manufacturers recomendation.

  4. Km81

    Km81 LawnSite Member
    Messages: 62

    All my equipment requires 50:1 and I only use Stihl Ultra 2 cycle oil. It make everything run a lot smoother, and its only .30 cents more than the cheap crap.
  5. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    They have a "Universal Mix" that covers all ratio combinations and it is a 'quality' oil.

    The biggest problem people have with 2 cycle engines is the use of 'cheap oil', then it's cheap gas, and if you're going to use the ethanol 87 Octane, forget it...

    If you don't trust the universal mix at least use premium gasoline and quality oil mix...
  6. Humbertslawncare

    Humbertslawncare LawnSite Member
    from SC
    Messages: 15

    Not to trying to take this post or anything, but this question does deal with the OP's question. If your bottle of oil for 2 cycle is for 2 gallons of gas, do you add exactly 2 gallons or do you use a little less gas?
  7. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,778

    Its not that critical.
    Posted via Mobile Device
  8. 24brookside

    24brookside LawnSite Member
    Messages: 10

    I am pretty sure the epa has something to do with those weak ratio recommendations.

    50:1 or 32:1...hmmmm now lets see. 32:1 is like 30 % +- more engine lubricant.
    Someone who tells you to run 50:1 or even 40:1 is not your friend or just does not know. I have seen a million stihl pieces laying around landscapers shops with the head pulled off and a scorched piston because they followed the epa/manufactures recommendations.

    1 can lawn-boy oil (8 oz) to 2 gal gas. (32:1) Like religion. Never a problem. never change the spark plug.

    I run my 2 stroke dirt bikes 24:1

    Just my .02
  9. RAlmaroad

    RAlmaroad LawnSite Silver Member
    from SC
    Messages: 2,257

    Important for everyone: About a year ago there was a big report with several repair shops for chainsaws, lawnmowers and weed eaters helping. The findings were that so many of the plastic lines were being melted by "Ethanol". Their recommendation was to use pure non ethanol gas. Most everyone in East TN use non-ethanol in their chainsaw, weedeater and lawnmowers. I had to take a Husky weedeater before the report came out; when I saw the repaired part--it was melted as the report mechanics said. Non ethanol gas is higher but not as high as a repair cost and you won't find it in the recommendations in the manual. A few words or a chance to sell another machine or engine part--think about it.
    Last edited: May 22, 2011
  10. FarmerCharlie

    FarmerCharlie LawnSite Member
    Messages: 26

    Thanks for the comments. As I expected, the opinions on this subject are not unanimous. I do use ethanol-free gas in all my equipment--mainly because some equipment may sit for a pretty long time between uses. But there is just one dealer left in my area that carries it; one went out of business, and the second quit carrying it. I guess I'll keep using the brand name 40:1 oils, and maybe back off a little on the amount of gas I add.

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