Engine Trouble can't get the engine to start...

Discussion in '2-Stroke Engines' started by ebay007, Mar 19, 2014.

  1. ebay007

    ebay007 New Member

    I'm new to this forum and to MB, but i'v been reading here for about two weeks and I didn't find something that would help me...
    I got a 80cc engine that says "Thunder industries" (i'm guessing its just a re-branded china stuff) and I did about 115km with it running 1:16 fuel ratio.
    It was all good until one day, about 3 hours after i rode it (and then it was all fine) I wanted to ride again but then when it started the engine (after a little struggle) sounded kinda weird and it died quickly. I managed to make it start for one or two times after that but it wouldn't idle and it would act weird. Now it wouldn't start at all.

    I checked for spark with three different plugs and its good, installed a new ngk iridium number7 plug, tried moving the clip on the carb needle one notch up and one down neither help so I put it the stock middle pos.
    I removed the carb (it the one with the black plastic air filter) and checked for the air filter foam and it had some oil in it that i thought might cause the air to not reach the engine so I soaked the foaf, I checked the carb intake tube gasket and it looks good) there was some of the gasket that "blocked" a little of the way so I cut it (I hope I didn't do any damage there), I replaced the muffler gasket cause it was leaking, removed the head to see if the metal gasket was blown and it was all good.

    Beside that I noticed that if I spin the rear wheel very slowly with the clutch engaged then the it would not keep its compression, is that normal? cause i'm only in the break-in and i kept under 20mph and not longer then 30min rides.

    So I really don't know that else to do...
    Any help is appreciated.

  2. ebay007

    ebay007 New Member

  3. BigBlue

    BigBlue Active Member

    16:1 is a heavy mixture. Your plug is going to get fouled. Try 20:1 and then go upwards. There are many posts here on what the proper fuel to oil mixture. Keep in mind that most engine sellers want you to use a rich mixture, so more than likely they won't have warranty issues. 16:1 hasn't been recommended for a long time. This was the mixture that my outboard motor used when using regular engine oil. 2 stroke oil and engine oil have improved greatly over the years. I use 100:1 with Opti-2 in all my 2 stroke engines, even in my HT engines. Most people are going to cringe at the thought of using 100:1.

    Here's a no start guide that help you troubleshoot your problem: https://docs.google.com/document/d/1aBeJuoS--VQWwXysc07rpscTUbPzgc93xjiQBgsyFjc/edit

    Good Luck,

    AKA: BigBlue
  4. V 35

    V 35 Member

    I also use Opti 2 100 to 1 in * all * my 2 cycle engines I like it. As for your bike, check for resistance [ compression ]
    with the plug out. No plug, clutch out, push bike, you should hear engine popping and hissing. If not = no compression, or crank isn't turning. Pull magneto cover, use wrench on crank bolt to see if engine turns.

    Could have sworn I blew my engine, but it was only a shattered small bevel gear.
  5. EastSideRider

    EastSideRider New Member

    it could be something obstructing your piston i'm currently causing low compression or none at all remove the head and crank case try turning the gear with your hand watching for piston obscurities
  6. ebay007

    ebay007 New Member

    thanks for the reply's.
    I looked at the guide but still can't get it too run. I managed to start it and ride a little but it sounds weird and sometimes it sort of chokes and it wouldn't idle. even if I close the needle as much as possible it would die. and and after couple of running like that it would wouldn't start at all.