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Thread: cranks, won't start

  1. #1

    Default cranks, won't start

    All, I've got a 99 AC 300 that has always been tough to start. I dont run it often, but when I do I always have to crank it to the point of killing the battery before it will fire off. Any ideas? Its kept in the heated garage, got plenty of fuel and a good battery (ok, now its a bit low since I been cranking on it till I killed it)...why cant I get this d***ed thing to start!?!?!?

  2. #2

    Default

    Make sure you have good spark, then check your carb. Sounds like something is gunked up in your carb but it could also be your spark plug. Another thing to check is your valves, my wife had a problem similar to this and we had the valves adjusted and that fixed the problem. 2 stroke or 4?

  3. #3
    Member walk-in's Avatar
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    Default try this

    Check the spark first because that is the easiest thing to do. Its probably fine. Most likely you have a carb problem. If you're comfortable with doing it, you can get an overhaul kit from the AC dealer. A friend of mine overhauled his on an old 454 a few months ago. Its not all that hard. You'll probably just find that it is gummed up, and a good cleaning will solve your problem.

  4. #4

    Default Throttle cable stretched

    A possibility, which fixed me earlier this year, was that as the cable stretches over time you need to tighten up the adjusting nut (on the handlebar) which takes up the slack in the throttle lever.

    It's an overspeed protection thing, which you see on snowmachines regularly; too much play in the throttle could be indicative of this.

  5. #5

    Default

    How long did the atv sit before you would use it? If it's months on end with the same old gas sitting in the tank I would guess a gummed up carb, like already mentioned. I'd go ahead and replace the spark plug too, atleast they are cheap.

    I've adjusted vavles on a v-twin. That was nothing short of a nighmare, but a thumper would be much easier.

  6. #6
    New member AKDSLDOG's Avatar
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    Default

    Look for dry rott on the fuel lines, you may be loosing your "prime". Blow into your gas cap vent tube to pressurize your tank a bit, if it starts easy then you are loosing prime.

    Check spark, pull the plug insert it back into the boot and hold the plug end really close to the eng. block, turn it over, do you see a nice blue spark? If so plug is good, if not, try a new plug, Or if you get a little shock (giggle giggle ) you have a bad plug wire.

    Air Filter, have you ever cleaned or replaced it? FUEL AND AIR make fire.

    Compression, when your plug is out, put your finger over the plug hole and turn it over, does it push your finger off the hole? Or is it weak?

  7. #7

    Default

    Quote Originally Posted by akgould View Post
    All, I've got a 99 AC 300 that has always been tough to start. I dont run it often, but when I do I always have to crank it to the point of killing the battery before it will fire off. Any ideas? Its kept in the heated garage, got plenty of fuel and a good battery (ok, now its a bit low since I been cranking on it till I killed it)...why cant I get this d***ed thing to start!?!?!?
    all...thanks for the tips...will get a chance to try your ideas this weekend...HOPEFULLY it's a simple fix and your info works for me.

  8. #8
    Member schmidty_dog's Avatar
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    Default Filters...

    Make sure if you have a fuel filter you change that. I know not many ATVs have them, but when I was young my dad had added an in-line fuel filter to our Bayou and that turned out to be the culprit with the hard start and sudden stall issues. Sometimes it would run fine, then quit all the sudden. We figured it must have been sediment in the filter settling out then clogging then settling out again.

    I would guess if not that it is probably the carb, but like the guys said, you need Spark, Air, and Fuel to run.

  9. #9
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    Default Engine basics

    Compression, fuel, ignition. Those are the basics for the engine to run. Ignition requires a blue spark. Remove the plug and make a cursory check for compression by holding your thumb over the plug hole when the engine turns over. If you have compression, check for a blue spark by holding the plug to a ground while turning the engine over. If you have those two, squirt some gas into the carb. Its gotta fire then unless there's loss of sufficient compression past the valves or rings or the timing is off.

    The key is to systematicaly isolate the problem to one of those three basics and then get detailed with what you find there.
    Ken

  10. #10
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    Default

    If the above recommendations don't work, I'd also suggest checking the compression. You may have a bad ring or valve not properly seating.

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