Fuel Mixture Ran a whole tank of gas with practically no oil by mistake!

Discussion in '2-Stroke Engines' started by relaxxx, Aug 11, 2012.

  1. relaxxx

    relaxxx Member

    I just got my tensioner and clutch working good and I pulled a really stupid move. I dumped a bunch of gas in my 2 stroke can without adding any oil. I was in a rush and though I'd do it later but forgot! There was a tiny but of mixed gas in there, maybe 10%. So after about a 30 minute run, just getting home I hear this really loud metal banging noise, not a good sound at all. next day sounded better but noise came back after 15 min. then I let it cool, and ran it another 20 min back home. After all that I then realized I had no oil in my gas. I mixed it up double strong, poured a bit of oil right in the spark plug and ran it a bit. It's louder than normal but running for now. Has a bad knock when turning over without the sparkplug. How screwed is this motor now?

  2. Fabian

    Fabian Well-Known Member

    Screwed - the motor is totally screwed - time to get a new crankshaft and connecting rod assembly and piston and cylinder. You will only make that mistake once.

    Before ever adding fuel - oil always goes in first, but it's easy to say that with hind sight.
    happycheapskate likes this.
  3. Fabian

    Fabian Well-Known Member

    I guarantee you that if you've never taken one of these engines apart, you will damage more things than you thought possible.
    If you manage to get it apart intact, you will most likely damage the motor getting it back together.

    If you have no experience rebuilding these engines, it will be cheaper and less frustrating to simply buy a new engine.
  4. bluegoatwoods

    bluegoatwoods Well-Known Member

    We feel your pain!!! At least, I can imagine how awful that would feel.

    You might consider riding it, if it runs and if you can stand the noise, until it craps out completely.

    No doubt Fabian is right; you might as well just buy a new engine for what they cost.

    And you could use the toast engine for rebuild practice. Then something good would come of this.

    Who knows? I might just end up following in your footsteps one day.

    I'll hit you up for advice.
  5. Greg58

    Greg58 Member

    The bad knock sounds like the small end rod bearing, you might want to pull the cylinder to see how bad it is. The 6202 bearings that are on ends of the crank are better at taking abuse than cage roller bearings are.
  6. V 35

    V 35 Member

    I'd spring for a new motor, get the same as what you got, your old motor has plenty of good parts. The cases are a bear to split and reseal
    [ properly ] You could buy a bottom end, and put your jug on it. for a few bucks more, pop for the motor . As for expense, what other vehicle can you do a $ 100 engine swap on ?
  7. relaxxx

    relaxxx Member

    Well it's still running. The really bad knock has not returned after a couple 30 min runs. I don't have the tools to take this thing apart and even have a look. I guess I'll just run it till it dies and then replace it.
  8. Fabian

    Fabian Well-Known Member

    It won't be long before it dies.
    Make sure you are not too far from home when it happens.
  9. HeadSmess

    HeadSmess Well-Known Member

    if it was me...

    id just keep using it :) who knows? it might just have fixed it! :jester:

    noise be noise! if it runs...run it! at least you can have a laugh when you do have to push it home...

    um...and it gets you moving til a new engine arrives... :)

    it would actually be interesting to see how long it willl last now... ;)
  10. adrian101

    adrian101 Member

    well that was a silly mistake.. buy a cheap replacement engine just in case.

    Remove the cylinder head and check the cylinder walls and piston. lube up the insides some with 2 stroke oil, check all rubber seals. Could run for miles more.
  11. relaxxx

    relaxxx Member

    I'm mixing it 20:1 now, before I was doing nearly 40:1. Running fine but the head is really loud. Like louder than the muffler, which is a paint can.
  12. Fabian

    Fabian Well-Known Member

    Really loud?

    Really loud, as like a 4-stroke car engine that has spun a big end bearing - are we talking "that kind" of "loud"


    are we talking "loud" like a turbo charged engine that has bent connecting rods from 38 PSI of boost.

    In both cases, you can still keep on driving the car if keeping an eye on the oil level and turning up the radio volume.
  13. nctrooper10722001

    nctrooper10722001 New Member

    Thats what I run.. Long legs and AV GAS
  14. nctrooper10722001

    nctrooper10722001 New Member

    Chrome alloy pistons are the cure.. Seems the pistons melt down if the f/a ratio on these cheap china parts arent met.. china sucks
  15. nctrooper10722001

    nctrooper10722001 New Member

    OOPS Im replying to my threads.. must be those china girls.. too bad they dont know anything about 2 cycle engines except how to ride one.. Maybe their didldos have an 80cc fake engine n it?? My Bad.. Just sayin
  16. Fabian

    Fabian Well-Known Member

    when you say the pistons melt down,

    do you mean a Fukushima meltdown; corium style where the cylinder head rapidly moves in opposite direction to the white hot piston as it flows out the exhaust port,


    do you mean like a Chernobyl meltdown where the bike is only partially incinerated, but the wheels still keep on turning.
  17. keatonx

    keatonx Member

    If the head is super loud, maybe the piston rings made a ridge of aluminum in the top of the cylinder wall that the piston taps every time it goes up. I'd check out the cylinder before the engine gets too messed up and see if that's the problem. You can just scotch-brite it off or use oven cleaner, which eats away at aluminum. Just wash it all off within 15 minutes so it doesn't cause any damage. But I think your engine will be fine. I've run a leaf blower engine with literally no compression, and what I originally thought was a bit of compression was just the magnet on the flywheel passing over the magneto.
  18. relaxxx

    relaxxx Member

    Still running pretty good. It has great compression, just loud. It was leaking around the spark plug so I put a bit of teflon tape around it. There's also a part of the head along the gasket that looks warped but it's not leaking even though it kind of looks like it should leak. I'm wondering if I should stay at 20:1 or go back to 30 or 40:1.
  19. Greg58

    Greg58 Member

    If its not fouling plugs or smoking a lot. And runs good why change?
  20. ballentinesr

    ballentinesr New Member

    Be sure to take your cell phone when you go riding. (For obvious reasons)