Backfiring?!?
 

Alright... so I've just got a ridiculous amount of carbureted carts that come in with backfiring. sometimes, a spark plug, or a new carb or an adjustment will fix it. Sometimes the gas is bad. But every once in awhile, we've got a cart or two that nothing seems to fix the backfiring issue.

What other options can we look at to try to beat this out? Ignition coil? Governor? Muffler? I'm stumped on a couple carts.

Re: Backfiring?!?
 

Depending on the cart, there are a few reasons for this happening. If you give more details to the carts you are asking about, we can try to explain a few reasons. Brand, engine type, backfiring through exhaust or carb? The list is endless lol.

The most common for backfire is the carb opening before the pedal switch activates the solenoid. Excess Fuel enters the engine before it fires and " Bang " next common is aftermarket carbs flooding and same thing, too much fuel too soon.
EZGO twin cylinders also suffer from worn inlet valves and popping back through the carb. In the early stages, valve lash adjustment can solve it. Very worn valves need replacement.

Re: Backfiring?!?
 

RXV with FJ400D and club car precedent FE350. Both with aftermarket carbs that don't seem to fix the problem. Thinking OEM carburetors?

Re: Backfiring?!?
 

I can't comment personally on the Kawasaki engines in those carts, but I do see it occasionally on the fj400's in John deere gators. It is usually operator error though. They turn the key off before stopping the cart and the engine draws excess fuel. Then when they restart it backfires. Not relevant to your situation though. I do see non oem carbs running way too rich on other machines causing backfires, so you may be on to something there.

Re: Backfiring?!?
 

Intermittent spark can also cause backfiring. A loose connection, bad point adjustment, etc. can cause it. Before you go replacing the carbs again, make certain that you have good repeatable spark.

Charley

Re: Backfiring?!?
 

So this is kind of what I was thinking, but can the ignition coil become intermittent if it's bad? Or is a bad coil just dead or alive?

Re: Backfiring?!?
 

Backfiring is invariably caused by the following process:

Ignition stops prior to fuel flow stopping and fuel continues to flow into the cylinder even though spark isn't occurring. Once ignition starts again, all of that unburned fuel is ignited at once causing the backfire. Here are the general causes and how to fix:

1) The throttle linkage isn't closing all the way thus allowing fuel to flow even though the accelerator isn't depressed. Lube and adjust the throttle cable / linkage.

2) Ignition is starting too late / stopping too early. On most carts, there is some type of microswitch that activates spark via accelerator movement. There is usually an adjustment associated with a microswitch somewhere. For example, on a Yamaha G1 the mircoswitch in integral to a "stop switch" at the base of the accelerator pedal. It can be adjusted in or out to make spark start earlier / later. It's critical to have spark start prior to fuel starting and stop after fuel stops flowing so that there is no excess fuel in the cylinder. If you can identify the "when spark starts" switch on whatever cart you are working on there is likely an adjustment associated with it.

3) Timing. Poor timing causes intermittent spark and backfiring. Points can be a SOB to time. Personally, I convert to electronic ignitions which rectifies most backfire issues. as timing becomes a lot more flexible.

To your question about ignition components, I think generally, they are alive or dead as you point out but sometimes there will be short-lived intermittent operation for a period prior to final death. There can be some backfire during those times.

Re: Backfiring?!?
 

Excellent info, thanks.