G21 Loud bang after driving it for a long time

[Altster]

Got a G21 running around that produces a loud bang when its being started after driving a long time (hour or so).

Anyone know what could be the issue?

It has the stock motor / carb. / muffler. It's only has a 2 inch lift kit.

[cgtech]

Probably backfires due to incorrect carb adjustment.. dont do it "just to the tee of the manual either". Its sort of complex (since there 2 cables & 4 possible adjustment points). It can be broken down into simple stuff, if someone hasn't already totally screwed it up. First, check that the throttle cable has at least a little "wiggle" when at rest. (If its tight when at rest, the second adjustment cant be made). Second, back off the throttle blade adjustment screw until there's a gap between the screw & throttle arm, then tighten it just a little smidge after it touches the throttle arm, just a little, like 1/16 to 1/8 of a turn.

What's happening, if my assessment of your problem is correct, is fuel is being allowed to pass through when the pedal is "at rest/not pressed", then , when throttle is pressed again, that fuel burns in the exhaust system, causing a "pop".

If you (or anyone else) has bypassed the governor, all this is out the window, and you'll have to get that advice elsewhere. I dont bypass governors. To me, the "benefits" of bypassed governor dont outweigh the potential drawbacks (possible axle & motor issues, plus it needs to be re-jetted, not stuff the "I just wanna go fast" rookie can deal with).

[Altster]

Originally Posted by cgtech

Probably backfires due to incorrect carb adjustment.. dont do it "just to the tee of the manual either". Its sort of complex (since there 2 cables & 4 possible adjustment points). It can be broken down into simple stuff, if someone hasn't already totally screwed it up. First, check that the throttle cable has at least a little "wiggle" when at rest. (If its tight when at rest, the second adjustment cant be made). Second, back off the throttle blade adjustment screw until there's a gap between the screw & throttle arm, then tighten it just a little smidge after it touches the throttle arm, just a little, like 1/16 to 1/8 of a turn.

What's happening, if my assessment of your problem is correct, is fuel is being allowed to pass through when the pedal is "at rest/not pressed", then , when throttle is pressed again, that fuel burns in the exhaust system, causing a "pop".

If you (or anyone else) has bypassed the governor, all this is out the window, and you'll have to get that advice elsewhere. I dont bypass governors. To me, the "benefits" of bypassed governor dont outweigh the potential drawbacks (possible axle & motor issues, plus it needs to be re-jetted, not stuff the "I just wanna go fast" rookie can deal with).

I picked up the cart yesterday. Governor hasn't been messed with. I noticed that the car only gives a loud bang/backfire with a hot engine , 1 or 2 seconds after it came to a complete stop. Not moving the gas pedal at all.

What could it be?

@cgtech

[cgtech]

First, check that the throttle cable has at least a little "wiggle" when at rest. (If its tight when at rest, the second adjustment cant be made). Second, back off the throttle blade adjustment screw until there's a gap between the screw & throttle arm, then tighten it just a little smidge after it touches the throttle arm, just a little, like 1/16 to 1/8 of a turn.

Be sure that the throttle blade doesnt begin to open before the motor starts turning.

Also, I have seen a Very Slight exhaust leak where the muffler meets the head contribute to this.

I understand it's happening when the gas pedal isnt pressed (which I have seen before), but carb misadjustments is how that extra fuel ended up in the muffler.