Discussion in '2-Stroke Engines' started by Bgard, Sep 18, 2013.

  1. Bgard

    Bgard New Member

    Ok guys I will try to give all info possible. I have tried everything I know to solve this. To much fuel is being blown back into the air filter. First off I have a grubee Skyhawk gt5a. 66cc. I have gauged the main jet at .025inches. I soldered it up and dropped 1 size to .024inches. No difference noticed. I has the nt carb. No air adjustment. Up to half throttle it goes good. Acceleration is good not to much vibration. How can I get it to blow less fuel out the breather. I know some is going to happen but it seems like to much. It will soak the back of the motor with oil. I mix at 32:1 standard grade oil. Hope you can help. I am 210 meters above sea level.
    Last edited: Sep 18, 2013

  2. IbedaYank

    IbedaYank Member

    it is a ported 2stroke.... it will ALWAYS blow some out the aircleaner as it has no intake valves to prevent this. Nor does it have any reed valves. Do some research on just how a 2stroke runs and you will understand why.
  3. HeadSmess

    HeadSmess Well-Known Member

    from my understanding you seem to be getting slightly more than just normal blowback if the things spraying it over the motor... you did say youd expect something...

    as yank says, tis piston ported. at certain rpm there will be a lot of backspray. at other rpm, there wont be any. nature of the beast.

    firstly. you jet the motor for performance, not backspray minimisation. ill forgive that, this once ;)

    what the :censored: is 0.025 inches?

    jets are one thing that is measured in MM. dont quote that. some are measured by flow rate. blah blah

    (and if you measured your jet as being 25.4/1000x25... lemme see now... oh no. 0.635mm. thats pretty normal after all... would be a 65 jet ;) down to 24 thou would give you 0.6096mm or a 60 jet. pretty standard. imperial drills can be handy for getting those "in between" sizes.)

    now. how certain are you that its the backspray?

    overflow on that carb feeds into the airfilter too...

    normally, if its overflow is an issue, floats are too high or stuck.

    and normally, in this case, the engine will flood.

    flood as in half your fuel tank will drain into the crankcase and the thing wont turn over until emptied out...

    you dont mention this happening so i can either assume this isnt the issue or you turn your fuel tap off all the time.

    meh. a dooozy :) pull carb apart if you havent already, make sure its guts are in order.

    sure its not a leak elsewhere? fuel line, gaskets...tiny lil leak and youll end up with an oily motor pretty quick.

    my $4.50 worth. pay up to purser :D
  4. Fabian

    Fabian Well-Known Member

    All piston ported 2-stroke engines will spit fuel back into the air cleaner, due to the principle of intake reversion, and will do so with greater quantity when run for extended periods at full throttle. Prior to fitting a Rock Solid Engines reed valve, my engine always had fuel/oil mix dripping from the air cleaner. Once the reed valve was installed, it completely stopped reversion; with not even a drop of oil or fuel leaking from the air cleaner.
  5. BigBlue

    BigBlue Active Member

    Or you can use Opti-2 at a 100:1 ratio. I run it in all my 2 strokes with no problems.

    AKA: BigBlue
  6. Fabian

    Fabian Well-Known Member

    It's fortunate that you have had no problems running 100:1
  7. Bgard

    Bgard New Member

    Thanks for your replies. I had forgot that I had tried a different float level. When I first mounted the carb I noticed that it was not level so I bent the clips down on the float levers. Than when I checked the carb I adjusted it to specs. That was why I had the flooding problem. Duh Old timers disease.