First mod I would do on a Spiderbox or other GY6

[toomanytoys2]

I just put a new top end on the Spiderbox that I am selling. Started right up and seemed to run good. However, after running the engines through the heat cycles, the carb started to flood. The fuel needle started to leak. So pulled off the carb an luckily I had some miscellaneous motorcycle needles and found one that looked the same. Threw it in and no leak.

So I took the Spider for its maiden voyage, and the thought that ran through my head was this thing is a dog compared to my HH (see sig). It ran fine and idled "OK", but not perfect. I remembered reading a thread about drilling out the plug cover over the mixture screw, so off the carb came again. Drilled a hole through the cover them popped it out with a screw driver and reinstalled the carb.

Fired it up and adjusted the mixture screw and got a really clean idle. Then I took it for a test drive and couldn't believe the difference. It was like it was a totally different engine. I had power now and more of it. I couldn't believe how much difference the mixture screw had made. So if your Yerf or other GY6 feels a little doggy and has the mixture screw covered, take out the plug and do a little tweaking, it may really open your eyes.

[Masteryota]

I believe it. Tom says all the time that those engines are tuned lean to pass the emissions tests here in the states. A little fuel goes a long way.