Engine won't start.

Discussion in 'Motorized Bicycle General Discussion' started by DarkWolf2k, Dec 20, 2016.

  1. DarkWolf2k

    DarkWolf2k New Member

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    80cc 100$ HT kit I'm guessing. Trying to help a friend get his started. Had a couple problems with it but nothing I couldn't figure out up to this point. Anyway. The thread on his back tire was bare so he ended up switching it for the front which was heavily warped. It ran good for a while (about 3 weeks) before the chain snapped from the tire being warped I guess? Got that fixed and now the engine will start and run for a couple of moments (a good 5-10 seconds or so) before cutting out with the fuel off. As soon as you turn on the fuel the engine won't start at all. I'm thinking it's flooded from him trying to start it though I have no idea. Any help is appreciated. Thanks.:-||
     
  2. Agreen

    Agreen New Member

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    Does fuel dribble out the intake with the shutoff open?
     
  3. crassius

    crassius Active Member

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    can't think of anything turning fuel on could do except make it over rich - I'd check float
     
  4. DarkWolf2k

    DarkWolf2k New Member

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    I tried it again earlier today and noticed it only wants to do it's "start" when it's been sitting for a while which is odd. I have some time off for the next few days so I should have time to work on it.

    @Agreen What do you mean exactly? It's got a small fuel leak on the gasket on the carb bowl from adjusting the float level initially when we first assembled and started to get things going. That's a matter of a little time of readjusting the gasket. It never seemed to sit right from the get go. Also; where the carb meets the intake there is an air leak (the common? one that's been documented on this site.)

    @crassius I haven't checked the float since I had to adjust it initially. I'll check it sometime in the next day or so since I have some time off.
     
    #4 DarkWolf2k, Dec 22, 2016
    Last edited: Dec 22, 2016
  5. Agreen

    Agreen New Member

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    Crassius and I were hinting at the same thing. If fuel runs out the air filter area with the shutoff open, it probably needs the float lowered a little.

    If the intake leaks, wrap some electrical tape around it and try again. Electrical tape is stretchy and can make a temporary seal to test it out.
     
  6. crassius

    crassius Active Member

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    if intake is steel, then you may have a bit of chrome sitting at the end that doesn't let the carb slide on all the way - file the intake a bit at 45degre angle right at the end, then be sure the carb goes smoothly all the way on
     
  7. StevenMain

    StevenMain New Member

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    It's the carb float height... bend the carb tab to shut the needle off sooner.. pull the plug out.. pedal your ass off for 1 minute. Put it back together and enjoy
     
  8. DarkWolf2k

    DarkWolf2k New Member

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    After thinking about the storm that hit a few days ago I decided to check all the maintenance and normal things. Pretty sure water came out of the carb drain. I let all of this flow out of the drain. No me gusta. Also where the electrical wires goes into the magneto casing let water into the magneto casing. I took off the other side where the flower nut is and all that to check for water there as well but there's only maybe a single drop so I don't think it's the gasket on that side. It seems to be transferring from the other side. Is there any way to push any possible water out of the engine? Just flooding it and running around without the spark plug in?




    @Agreen There's a little bit of fuel residue on the air filter. Basically the needle should shut off fuel from flooding the engine but this isn't happening is what you're saying I'm guessing. I've got some electrical tape lying around so I could try doing that. I was thinking about some sort of rubber car tubing or something to go around the air leak that crassius was talking about filing down. I do have a metal file though. I'll try turning on fuel again and see if it comes out of the air filter.

    @crassius It's a very small ways from being all the way on and I do believe it's steel. I'll check with the friend to see if this is something he'd be willing to consider.
     
  9. StevenMain

    StevenMain New Member

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    Alright or ignore me completely despite the fact that it could fix you in litterally under 5 minutes .
     
  10. DarkWolf2k

    DarkWolf2k New Member

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    @StevenMain Sorry, I meant to reply to you as well. There was water coming out of the drain on the carb which makes me not want to try it until it's been flooded with gas a bit again. I think I'll probably work on getting the gasket done on the carb then try what you were talking about, then letting it go with a little gas, then doing it again.

    @Agreen I turned the fuel on and let it go for about a minute. No fuel out of the air filter at all. Or any leaks besides the carb bowl gasket that I can tell.
     
  11. sbest

    sbest New Member

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    There is a mechanical maintenance trouble shooting principle of putting everything back to the "as designed" state to start the troubleshooting process. The next principle is to look to see if you have everything you need to make it go. Fuel, air, compression, spark, and timing.

    So, first of all, fix all the little problems, loose bolts, missing parts. Then:
    1) Fuel, pull the fuel line off at the carb and drain some fuel into a glass jar.
    - does it flow well? Is it clean?, Does it have water in it?
    - Is the carb level? Leak free?
    - Did you set the float level? A nipple to the drain with clear line is the best gauge.
    2) Air, is the air filter clean and clear? Is the carb and intake well sealed? Exhaust clear?
    - Crank seals and gaskets? I do a 4-7psi leak test to check these.
    3) Compression, over 110psi?
    4) Spark bright yellow and audible "click"? Clean or new plug, right type?
    5) Timing not changed from when it ran? Did you have it apart? 1 o'clock at TDC?

    By checking the clean plug you will know if it is flooded or not getting fuel.

    The answer is in there somewhere...

    Steve
     
  12. DarkWolf2k

    DarkWolf2k New Member

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    Got the carb bowl gasket fixed so that's all good. Thinking I'll probably run it with the spark plug out now and then let it have some more gas and do it again a time or two to run out any possible water in the engine.


    @StevenMain Should I still adjust the float if it doesn't have gas coming out of the air filter with the petcock open?
     
  13. sbest

    sbest New Member

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    Gas running out of the carb is a stuck needle valve. Needs to be cleaned.
    Float level check is one of the primary carb checks.
    Cleaning and float level check is first thing you do with carb problems.

    Steve Best
     
  14. Agreen

    Agreen New Member

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    If fuel is not coming out of the air filter, then it probably isn't a float issue. It's a common issue, but probably not your problem.

    If you (or your friend ) let it sit outside and it had water in the magneto cover, open it back up and hose it down with WD-40. The WD stands for "water drying". No, seriously. You could also disconnect the kill switch if that doesn't work, since it creates a short when pressed, but could have water in it.... causing a short.

    But most importantly, do what sbest has said. It's a good troubleshooting guide to follow.
     
  15. DarkWolf2k

    DarkWolf2k New Member

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    The carb bowl gasket wasn't seated properly when it was shipped. After fixing this I have no more gas leaks as far as I can tell. It might have had something to do with my friend trying to re-seat the gasket as there was a significant amount of debris in the float bowl. I cleaned this and checked the main jet? I guess it's called. To make sure gas flowed out. I probably skipped a lot of steps I would have done on one that I owned but my friend isn't exactly friendly with how he treats his bike.
     
  16. DarkWolf2k

    DarkWolf2k New Member

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    After a lot of headaches of trying to figure it out, doing routine maintenance stuff like tightening down loose bolts, etc. I got it to run just fine. Turns out the clutch was slipping quite a bit. I didn't adjust the float at all cause no fuel was coming out of the air filter. I did take Steven's advice though and took the spark plug out and ran it without for a bit to unflood it I guess? I dunno if it helped but it's running so hooray. Thank you everyone for your replies. dance1
     
  17. Agreen

    Agreen New Member

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    If I had to guess, I'd say it flooded when you had no spark from the magneto being wet. Once it dried out, the case was probably full of fuel, and blowing it out solved it.

    Good work!
     
  18. DarkWolf2k

    DarkWolf2k New Member

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    Had it running for a few days and it would bog if I let the fuel on before starting it. Once starting/running with fuel off and I could turn the gas on and it would act completely normal. Now it will start whether fuel is on or off and seems to completely bog unless you're pedaling about as fast as midway throttle to as fast as you can possibly pedal. Then it'll sputter a bit at mid-high range, produce some power, and eventually die. I've done a complete breakdown and rework from the gas tank to the intake on the engine. Checked gas tank, petcock, fuel lines, in line fuel filter, carb reassembled. Checked gas before putting it in the tank and all seems okay. Nice blue tint and no particles.
     
  19. DarkWolf2k

    DarkWolf2k New Member

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    Also; if you start and run it with gas off and continue pedaling it will eventually stop sputtering and just bog completely. It seems like a gas problem like it's starving but everything I've checked seems fine. The carb is just slightly off level.
     
  20. Agreen

    Agreen New Member

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    Terminology time:

    4 stroking - when the engine is "sputtering" or has that "machine gun" feel. Due to having too much fuel (rich)

    Bogging - A notable drop in power, without any other strange noises. Sounds like (and feels like) the engine is just spinning down and not producing power. This is due to a lean condition (too little fuel)

    Now, the situation you described above with turning off the fuel sounds like it is just normally running too rich. Once the bowl starts to empty, you start to experience a short moment of correct air/fuel mixture and it runs good for a second, then runs out of fuel and bogs entirely.

    That could mean a couple things. One possibility is that you are running your oil mix too thin. More oil per part of gas makes the air/fuel mixture more lean. Less oil means a more rich condition. You're experiencing a "too rich" condition, so try a higher oil/fuel ratio? What is yours currently, and how do you mix it?

    Another cause can be the needle. It's connected to the carburetor slide with an "e-clip". Move the clip up to go lean, but this only adjusts air/fuel mixture up to about 3/4 throttle.

    If changing your gas/oil mix and moving the needle doesn't help, I'll step you through re-jetting the carb.
     
    #20 Agreen, Dec 27, 2016
    Last edited: Dec 27, 2016

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