1983 Marathon Backfiring

[junior flyer]

Hi guys,

I have a 1983 EZGO marathon that is having some issues with backfiring. This has the 244cc robin 2 stroke engine. It is happening when i come off the gas to come to a stop and then hit the throttle to get going again. I have searched high and low in the forum for advice on the issue and have got things adjusted with the throttle spring to what seems like should be good (micro switch closes prior to the throttle moving at all). I have even tried with two separate carbs and get identical issues with each.

I have tightened up the exhaust on the cylinder as well as the joint in the exhaust pipe. I have new gaskets on the way for that just in case that could be causing it. I also ordered some new crank seals. I am not sure if that would cause this issue or not.

Everything else on the cart seems to be perfect. I just purchased it a few weeks ago from a fellow who said it was running poorly and that it was super loud. He didn't even have the exhaust tightened on the cylinder and the piston was installed backwards. Now that those issues are fixed, the thing runs like a clock, but this backfiring issue is annoying and I am struggling to find a solution.

Please let me know what you think could be the culprit here.

Thanks for any help in advance.

[cart around]

I'm on my phone so this will be short. It sounds like the throttle is not completely closing. There is a screw on the side of the throttle shaft that can be backed out to make sure that the throttle plate is completely shut. Post some pictures of your carburetor.

[junior flyer]

I figured the same thing. I backed out that little screw on both carbs. I’ll grab a couple photos of the carb shortly.