Exhaust Raw mix gushing out nthe exhaust

Discussion in '2-Stroke Engines' started by uncle_punk13, May 9, 2009.

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  1. uncle_punk13

    uncle_punk13 Guest

    I have been searching the various threads with the search engine and haven't found what I'm looking for, so here's an interesting thing- My Tanaka 40cc is now having a hard starting problem (all the time not just when warm), and it seems after a dozen to two-dozen rips of the cord, When cold, it sputters to life and a HEAVY stream, and I mean heavy as in someone has turned on the garden hose, of fuel mix comes spraying out the exhaust, it lessens up and stops once the engine is running. When i shut it down after a ride it smokes excessively from the exhaust. I assume from the fuel oil mix spray. Did I blow a ring or something? It still buzzes right along at 32-35 M.P.H. but this whole fuel thing is very not good... Did I screw up the engine running it too hard too soon (I admit I am prone to doing that...) Or did switching to the Lucas mix cause my engine to vomit?
    Thanks in advance fellas (and ladies).

  2. bamabikeguy

    bamabikeguy Active Member

    I tried a 40 cc when they first came out, only kept it a month or so, then sent it back for a replacement 33.

    So I didn't have it long enough to remember the carb. issues, (though I remember a fuel line coming loose and doing a "garden hose" action. I think my "side of the road" fix was twisting a wire on the fuel lines.)

    Running it hard at the onset MIGHT have done something, but what I would expect the result to happen would be lower top end or lower compression, not a change in the gas intake.
    Last edited: May 10, 2009
  3. uncle_punk13

    uncle_punk13 Guest

    Well My gut feeling, though I didn't mention it in my starter post, is the carb., and maybe specifically the diaphragm. Though it would seem (to me anyway) if the diaphragm were stretched, worn, or torn it wouldn't pump as much fuel or any fuel, rather than wayyyyyyyy too much. I'm currently downloading and researching the PDF from Tanaka website. I'll call them Monday and see what's what, and let y'all know so if anyone else has this problem, the cause and fix will be available for them here... I've never had any of my two-strokers do this; it's just the strangest thing I've seen! :grin5:
  4. augidog

    augidog New Member

    hi rif.

    the impression i get is that the tanakas are ready to run right out of the box...my reasoning is that "who's gonna buy a leafblower and take it easy for a year?" now, i realize that we put more load on the things than a leafblower, but you DO seem to have a unique problem with your 40. 'cruzin has a stock 40, the plug always shows a pretty lean condition, but starts and runs like the proverbial molested ape. my 40 started it's life with an HP carby, a bit harder to start, but it also seems to prefer leaner mixes.

    i don't think it would have anything to do with the lucas oil...dennis himself gave me the go-ahead to use it.

    at this point, i would concur that it has to be a "seal" issue...but i'll be interested to learn about what you find....do you think it's sitting on the shelf so long had anything to do with it?
  5. uncle_punk13

    uncle_punk13 Guest

    Thanks fellas!
    I concur about the usage/break in. I really didn't think the Lucas had anything to do with it, but these are the factors that changed, and it only started doing this upon my return from O.P. so had to mention it. Perhaps my 75 mile commuting weekend had something to do with it? I dunno... And Yeah, I've considered that sitting in various locations (some less than ideal as for climate conditions) over the years before using it could certainly be a contributing factor. I found the ident. tag for this engine- I got it in 2000, it sat around until '08? So figure at least 7 years it sat around and could have certainly deteriorated some seals, perhaps some corrosion... Who knows.
    It would amaze you how much raw mix comes flying out the exhaust, it's really not an exaggeration when I say, shake up a can of soda, then pop the top; it sprays out like that... I've NEVER seen such a flooded condition, ever! BUT like I said, it doesn't seem to affect performance once running and the crankcase/cylinder is cleared- she zips right along at a nice 32-35 tops, and pleasantly buzzes 30 typical cruisin'...
    Tell ya what though, if the thing is shot (I don't think so, just carb stuff IMO) I'll trade up for a 47-r; that's the meow ain't it?
    OH, almost forgot to add- now have about 300 miles on it.
    Last edited by a moderator: May 10, 2009
  6. The needle (rubber tip) isn't seating in the carb.
    That is causing too much fuel to pour out the carb into the motor.
    Take it apart and clean the needle, internal filter,
    and seat. As long as it isn't too damaged, you might get away with a cleaning,
    or might need a carb rebuild kit. If the seat is very damaged, you'll need a new carb.

    Be careful, because once this starts dumping, your engine will be full of gas.
    My Bluebird 52cc I just got has the same problem.
    Rebuilding it today.
  7. augidog

    augidog New Member

    good info, captured'...that's more than i knew a minute ago, thanks.

    rif, good luck snagging a 47, "r" or otherwise...the last one (r) i saw went for $355 on the 'bay...foolish me thought a mere $335 would win it. one vendor site had both listed for sale, but that was just a poorly run site and only served to get my hopes up and dash 'em to the ground...so, i gave up on getting a big tanaka, and went shopping.

    for a nice bit of displacement for the money, have a look at this "scooter" 49cc: http://www.motoredbikes.com/showthread.php?t=19457

    let's put it this way...i'm keeping up with traffic ;)
  8. Just found my culprit,
    someone put the wrong metering spring in for the needle.
    Thus the carb pouring fuel into the motor.

    They must have lost the one it came with, and didn't realize
    that the spring has to be exactly the right tension, or thing will get funky real quick.
  9. uncle_punk13

    uncle_punk13 Guest

    Thank You so much for that "Hip-Tip"! If I need to rebuild the thing I'll just hold off for a few weeks (I just spent what little money I had saved on a 1970 Firebird the other day, so I am completely broke for a while till the machine shop calls me back to work) and buy the "package" from Tanaka:
    Wow- that 47-R is a spendy little bugger isn't it?!? Probably worth it though...
    This is a great little tidbit of info and I can't thank you enough- I was completely flabbergasted at the sight of this- It did it three separate times now, and I was just like, astounded at the AMOUNT and pressure, at which fuel was flying! Now, there is a topic on this with probable cause, and solution, so if anyone else has this problem, they won't be left out in the cold with it. :)
    Thanks again all for your responses...
  10. I am willing to bet you just need to clean the parts well, and reassemble.
    The needle has a rubber tip, and as long as it looks clean and not busted up
    just use carb cleaner and spray out everything,and you'll be riding again.
    (just an FYI, to get to the needle, you have to take out the metering arm
    and there is a screw that holds it in, remove it and the needle can be pulled out.
    Watch out that the spring does not fly out and get lost!)
  11. stude13

    stude13 Active Member

    hi unk, could it be a fuel and water mix spewing. i once hauled a bultaco in the rain. when i tried to start it a mix came out of the pipe.
  12. uncle_punk13

    uncle_punk13 Guest

    Hey Stude13!
    I thought maybe that was it the first two times it did it, as On the way home from O.P. it rained HARD the whole run home, then the second time this happened I had left my bike out in the rain overnight, but this time it had been locked and stored in the shed- no rain could get at it, that's why i finally posted about it... It doesn't do it every time though, I just went out, no priming, no choke, cold engine, and she fired up first pull with no spray or other strangeness. So I'll pull the carb. clean it all up, check the condition of everything, re-assemble/install and probably change/upgrade the plug while I'm at it; then we'll see what is what... Good to see yer still around buddy!
  13. eastwoodo4

    eastwoodo4 Member

    if the gas in your tank is lower than the engine this would never happen.with the gas higher than the engine and a dirty carb u get a motor full of gas.
  14. You are mistaken, my friend.
    It can and does happen regardless where the tank is if the seat gets stuck open.
    As soon as you give a pull start, the case is pressurized, thus drawing fuel in.

    This has happened to me 3 times on different motors, all with tanks lower than the motor.