2 Strokes: 40:1 50:1

Discussion in 'Homeowner Assistance Forum' started by bobw, Sep 12, 2007.

  1. bobw

    bobw LawnSite Senior Member
    Messages: 807

    I increased the body count of 2 stroke engines in my garage from 1 to 2.... (added a blower to go with my trimmer). One needs a 40:1 mix and one needs a 50:1... so... is there a way to live without having to have two separate mixes?
  2. Jay Ray

    Jay Ray LawnSite Fanatic
    Messages: 6,510

    I think some guys are using Amsoil synthetic at 100:1 in all 2-cycle.

    I use the orange bottle (stihl) exclusively for 50:1 and any old mix on any retail shelf for my 40:1 equipment.
  3. BostonBull

    BostonBull LawnSite Senior Member
    Messages: 520

    ust mix everything at 50:1. With the new engines coming out like Redmax, Husky, and Stihl stratofied engine. And especially Stihls new 4-mix engines anything richer than 50:1 builds carbon like you wouldnt beleve and will eventually gum up the units.

    The old adage of the richer the bettter is just that old. Oils have come so far in the last ten years that there is no need to run rich mixes.
  4. mdlwn1

    mdlwn1 LawnSite Silver Member
    Messages: 2,443

    I raced motocross for many years. You can run 40-1 on the larger 2-cylce motors with no problem. For testing purposes we have gone to 22-1. Quality oil doesn't really gum up. I wouldn't recomend going against manufacturer. Having said that, I run45-1 in my rdmx 8001. On the smaller stuff..it gets to be real important that the mix is right on. Also, if you are using echo (all have been switched to a single ring piston) it might be a good idea to richen things up just a little bit as the piston is not likely to last long otherwise. And that is from the dealer
  5. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Messages: 2,524

    Jay Ray is right.

    If you can get some Amsoil synthetic or Opti-2, you run them around 80:1-100:1. Sounds crazy but I've run all my equipment for years with Opti-2. Your situation is a big reason they made their product that way.
  6. nmurph

    nmurph LawnSite Senior Member
    from ga
    Messages: 668

    i agree with much of what has been said regarding advances is technology and you may find that there are people that get by, disregarding the manufacturers specs or using "high-tech" oils. but for me, i would spend the $5 to buy a seperate can and another few bucks for fuel stabilizer. two cans, two gallons of fuel, some stabilizer, and some spray paint to differentiate the cans.------simple
    i anticipate that you don't think that you will use that much of two different types of mix, and that they will degrade bf you use them. i use about 2 gals of mix per yr. the second gal was prepped the other day. it will last me the rest of this summer/fall and be good-to-go when i fill up in the spring. i don't drain my two stroke stuff (all supposedly hard-to-start stihl), or either of my mowers, over the winter and don't have any start-up problems in the spring. i grabbed my ms 310 chainsaw the week bf last and it cranked on the the 5th or 6th pull. it had not been run since mid-summer '06.
    manufacturers don't just pull these ratios out of their hat. they are based on testing, and the engines and fuel systems are designed to utilize the specified ratio. it is just cheap, simple insurance to follow their guidelines.
  7. dfischer

    dfischer LawnSite Member
    from Il
    Messages: 114

    ah the stuff that gets onto the internet....

    Amsoil "mixed" @ 80 or 100 :1 isn't REALLY 80 or 100 :1 as most tend to think. The base viscosity of amsoil is twice that of most hi-quality oils. So, amsoil sounds like a superior oil when it's really a "true" (and I'm playing loose w/words to make a point) mixture of 50:1 (relative to other fuel oil mixtures). after it's mixed. Note your pour half of much of it in compared to other oils... Thats because it's twice as thick... Not a better oil, just thicker.

    So, the problem of what ratio to run isn't resolved by amsoil...

    Next, some, maybe even most, full synthetics can both attract moisture and will (as a separate problem) wick oil off of metals fast enough that an off-season off no use can result in rust on oil bearing surfaces. Note the two issues in this paragraph can combine to create a less then perfect situation for off-season storage. For these that run year around its nbd, but otherwise a semi-synthetic seems a better choice.

    As has been said, a decent oil won't gum @ any viable ratio. When in doubt, run a bit rich (as has been said) and a bit more oil. Certainly 40:1 is not to much oil, and it's unlikely to lean out the engine that was @ 50:1. Do note the above lean/rich issue. If you add more oil to the mix you are slightly reducing the fuel being metered and the engine will run slightly leaner. And vice versa. These aren't big changes, but might affect an already margin tune...

    For hi-performance stuff I run Motul 800-2t (litre bottle's) @ 37:1, and fog the engine out in the fall w/the std fogging oil. 37:1, btw, is just a number I use that is easy to mix. Motul comes in liter bottles. The point is I wanted a bit less smoke then 32:1, better protection then 50:1, and easy to mix..

    And do realize we're only taking about a little smoke output here. Todays better oils burn clean enough that gumming only happens to guys buying cheap oil. Power output changes aren't significant and jetting changes fix most of that. Running low oil mixes (high ratio numbers) is pretty hard to justify...

    As for what oil to use, I've consistently heard pretty good things about yamalube 2-r. I keep it around as backup oil for the Motul and as a day to day oil for the lawn stuff. It's fairly cheap, well respected, easy to find, and semi-syn based. What's not to like? I mix it to a "strong" 40:1 and leave it at that. I think you'll find a gools search will show a lot of 2-stroke power users trusting it: Aviation, snowmobile racers, MX, boaters, and chainsaw users all seem to have found and switched to it.

    Note 40:1 is pretty close to both 32:1 and 50:1. The oil is good enough to protect the 32:1 demanding engine and doesn't screw up the jetting of either of the two extremes enough to matter most times.

    And so my summary: 40:1 with a quality semi-synthetic oil will support 99% of the 2-stroke publics needs and will allow:
    * only 1 pre-mix can of fuel
    * Fresher fuel (since you're not keeping stores of lots of different mixes)
    * No confusion
    * No off season storage issues
    * no compatability issues w/other oils (for you bean lovers out there)

    Finally, since we're talking about 2-strokes, I rather strongly believe they need a good spark-plug to run well. I'd suggest taking out any champions, running only autolite or NGK, and keeping a spare handy. Do that, jet a bit to the rich side, and keep a pre-oil foam filter in and most 2 strokes are amazingly reliable.

    luck to all,

  8. Jay Ray

    Jay Ray LawnSite Fanatic
    Messages: 6,510

    I keep my different mix cans very clearly labeled, and seldom have 40:1 on the truck, only for a saw. Never a problem. With 114 heat factor in August I almost poured pure gas in the BR-600 however. Was taking the cap off when I realized what I was doing. Got to the Gatorade/shade fast to get rid of the fog.
  9. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,778

    I would run 40:1 in both units. There is not much difference when you really think about it. Run the high quality synthetics and you should have no problems.

    On the otherside of the coin, 50:1 with modern engines utilizing chrome bores and chrome rings could nearly run without oil so you should be fine with 50:1 in both engines.
  10. nmurph

    nmurph LawnSite Senior Member
    from ga
    Messages: 668

    so why not use quality dino oil mixed at the correct ratio and supplemented with a stabilizer?

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