1986 G3-a backfire problem

[claybyrum]

Hi all. I have just recently purchased a 1986 Sun Classic. The cart had been sitting for awhile when I got and was running fine. It recently has developed a backfire problem once the engine heats up to normal operating temperature.

I have drained and flushed out the fuel system, changed the spark plug, checked the air filter and cleaned the carb to no avail. This is a 2 cycle engine. Does anybody have any ideas on what could be causing this?

[spriddle]

Usually this is due to the throttle on the carb not closing all the way when you release the gas pedal.

[claybyrum]

Unfortunately it backfires when I'm still on the throttle going a constant speed

[spriddle]

Check the valve going to the muffler. More than likely something in the carb linkage is out of sync. I'm not too familiar with the G1's/G3's so maybe one of the guys here will chime in. I'm betting it will end up being with the linkage or that muffler valve. I've heard of some people removing the valve on the muffler.

[claybyrum]

Thank you. I will give that a try

[claybyrum]

I pulled the muffler off and the butterfly valve seems to be operating normal. Other than the backfire problem the car runs graet. Does anybody have any other ideas?

[spriddle]

Not sure if these have a regular valve adjustment or not like the G2/G9's. Here is a link to Yamaha's site that might give you some more help. I skimmed through the owner's manual. Carb section is around page 45 or so:

http://yamahagolfcar.com/partsandser...rsmanuals.aspx