Possibilities.... </p>
1) Electrical......Stator.... Actually dropping voltage. Coil getting hot and shorting internally. Powerpack..Transistor failing to trigger compacitor. Timer base... Failing to trigger transitor. ANY of these can be tempature sensative. </p>
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I would take a timing light and install on each wire and see if it is flashing or quits flashing when it bogs. Anytime voltage runs through a wire, it will trigger the light to flash. This will not measure voltage, just if it is present. If it is dropping a cylinder then you have to identify why. I have special tools to test the ignition system. There are some test you can run, but we will discuss those later if you identify you are loosing spark.</p>
2) Fuel issue. Is the bulb sucking together? When it bogs have you pumped the bulb? </p>
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If it wasn't for the running good then bogging, I would probably say the timer base is sticking. I have seen it alot that the trigger (timer) will stick. The thing with 2 strokes is you have to advance the timing to accept the fuel. Sometimes they will stick and not advance the timing. This will cause a BAD bog. The trigger is the portion under the flywheel that has a link to the "arm" on the side of the engine. When you move the throttle you will see it move then it will stop and it "breaks" away and finishes opening up the carbs. I have also seen the ball that the linkage goes in break and the rod have alot slack. But you said it will run good then poor and this wouldn't cause it to bog after it gets going. Unless it is the ball on the linkage. But they usually just bog. Hope this helps.</p>
