So, twice in the last week it was running perfectly, but then the next day you had a lower battery charge than expected? And the second time it was a brand new battery? I think I would check for a phantom load. Maybe something isn't turning off when the key turns off? Is there any current being drawn when the key is off?

 

Oh, and I think the pow is a symptom of the problem, not the cause. If you're turning the engine over, but it's not starting, you're exhausting unburned gas into the muffler. Eventually you get it to fire once or twice and it's enough to push a flame out of the wet cylinder and.... pow.

Think of it as a sign you're getting gas.

 

Lol. I always jump when the "pow" happens. When I pulled the carb off, there was gas inside and that answer the question, "Are you getting gas?". I wasn't quite sure why it was doing that so I wanted to get an answer why it was. So, this sounds like to me that either the spark plug is not giving enough spark or the battery is being drained by something and isn't giving enough power.

 

And if you don't have enough battery, you won't have enough spark. At least that's a theory that seems to fit the symptoms. On bikes with batteries, the magneto charges the battery and the battery provides the spark. So either something is draining it at night, or the charging system isn't working properly. The phantom load is easiest to test.

 

Call me out if I am wrong, which I probably will be. The magneto is on the flywheel correct?

 

Yes, it's the magnets on the flywheel that spin past the coil of wire mounted underneath called the stator that produce electricity. Even though technically the magnet portion is the magneto, sometimes the term refers to both parts. There is also a regulator involved that converts the A/C put out by the magneto/stator to D/C to charge the battery.

 

Ok. This is starting to sound like what was happening to our Bobcat 873 Skid Steer. The alternator went bad and was draining the battery. I don't think there is an alternator on ATV's or is it the regulator that you are talking about?

 

An alternator is a magneto, stator, and regulator all in the same case. Easier to replace, but they take up more space.

 

The 300 Bayou barely has anything electronic on it if you think about it. The current generation of ATVs have so much electronic equipment on them. What could be draining the battery while it is off on the Bayou? (I cannot think of anything that would drain it xD)

 

It could be a short in something like the regulator. A frayed wire could do it as well and might be an intermittent problem. As a kid I had a honda 110 that would quit if you turned the bars all the way to the right because that would make a frayed wire touch the frame.

Testing for a load will rule all of this out or in.