Why Does My Golf Cart Backfire? Common Causes Explained


Why Does My Golf Cart Backfire

It’s a beautiful day in the neighborhood, and you are enjoying the peaceful morning drive, headed down the golf cart path or walking trail. Nothing is more irritating than having an occasional backfire (or series of bangs) when pressing the accelerator pedal or coming to a stop. 

Golf cart backfiring is a result of the throttle plate not being fully closed when the microswitch engages the ignition, in most cases. When the throttle cable is out of adjustment, the throttle plate never completely closes, allowing unburned gasoline to accumulate in the exhaust system before the spark plug fires. 

Here are a few tips for adjusting your golf cart engine to keep it from backfiring.

How To Fix Golf Cart Backfiring

1. Golf Cart Backfires When Throttle Plate Doesn’t Close Correctly

For your gasoline-powered golf cart to operate properly, the microswitch must click before the accelerator throttle plate moves. Here’s the first thing to check before delving deeper into your backfiring problems.

Be sure the Ignition key has been turned off and the seat has been removed so that you can observe the throttle action. Gently and slowly push down on the accelerator pedal until you hear the microswitch click. The microswitch is usually located at the pedal or just inside the engine compartment. The throttle plate should not have moved before the click was heard, but if it did, then you need to adjust the throttle cable.

Golf Cart Throttle Cable Adjustment

The mechanics of golf carts differ between manufacturers and makes. Your model may have a throttle cable that slides through a hole in the throttle lever and is secured with a screw or stop nut. Adjustment is made by loosening the nut or screw, pressing the throttle closed, and then retightening the nut.

Some golf carts may not have accelerator cables but instead will have a series of rods between the gas pedal and the carburetor. The last rod in the series will usually need to be adjusted in length to allow the carburetor throttle plate to close fully.

If none of these accelerator cable adjustments solve the problem, then the throttle plate may not be closing all the way due to an obstruction or internal mechanism being bent. Unfortunately, the only way to find out if this is true is to remove the carburetor and inspect it. If you do end up having to remove the carburetor, when you replace the gasket between the cylinder and carburetor it will eliminate yet another possible air leak.

2. Golf Cart Backfires Because Fuel Mixture Is Too Rich

Always check the air and fuel ratio to make sure your engine is not receiving too rich of a fuel mixture. The following adjustments are an example of most carburetors, but you should look up the proper number of screw turns your model requires.

2 Cycle engine: The adjustment screw is on the side of the carburetor and is parallel to the ground. You can identify it by the lock nut at the base of the screw. Loosen this and turn the screw all the way into a soft seat, then back it out one and a half (1-1/2) turns.

2 Cycle Carb Adjuster

4 cycle engine: This has a plastic cap limiter on the top of the carburetor, and there is a minimal amount of adjustment needed or available with this model.

4 Cycle Carb Adjuster

Some experts suggest removing the drive belt first, then backing out the fuel adjustment screw while the engine is running. Once the engine is running at it’s best, the lock screw is tightened down, the engine is shut off, and the drive belt is replaced.

3. Golf Cart Backfires Because Of A Carbon Buildup On Piston/Valves

Another possibility (though less likely) reason for your golf cart backfiring can be a buildup of carbon on the piston, also known as coke. This material glows red hot after the engine runs for a while and ignites the fuel without the spark plug being turned on. The remedy for this condition requires removing the head to get to the top of the piston.

If you find that there is a buildup of coke on the top of your piston be sure and use a blunt tool to scrape it off because the piston material is very soft and can scratch or gouge easily. A scratch or gouge would glow red at the edges and cause just as much of an ignition point as the original issue would have and would defeat the purpose of de-coking.

4. Golf Cart Backfires Because Of A Carbon Buildup In The Muffler

The last thing to check on this list is the muffler. The muffler can get a buildup of carbon/coke and ignite unburned gasoline. It sounds crazy, but the common method of un-coking a muffler is to remove it from the cart and barbecue it over a fire for about half an hour. This will burn off all of the debris inside the muffler and turn it to ash.

You will then let the muffler/exhaust system cool down, after which you turn it up on end and tap the sides to dump the ash out.

Related Questions To Golf Cart Backfiring

How Do I Clean The Carburetor To Stop Backfiring On My Golf Cart?

Cleaning the golf cart carburetor will require you to obtain a rebuild kit, or at the very least, a gasket kit. The gaskets and seals will not re-compress properly if you try to reuse them. If you buy a kit online, specify the year and make of your golf cart and make sure that it includes the main jet and gaskets required to finish this job.

It would be a good idea to get a brand new gas filter and air cleaner filter while you’re at it as these are fairly inexpensive and will ensure a complete job. Periodic replacement of the fuel pump is also recommended since they are very inexpensive.

Begin this process by turning off the fuel line to the carburetor. If your golf cart does not have a shut-off valve, merely disconnect the fuel line and pinch It off or plug it with a screw.

Remove the air filter cleaner and all lines and accelerator cable linkages attached to the carburetor. Unbolt and remove the carburetor from the engine body and we can begin disassembly.

Before removing the air mixture screw, turn it all the way in (gently) to a soft seat and count the number of turns. You will want to put this back in the same position when you are done. If you find that it is 1 and 1/2 turns from a soft seat, you’ll want to reinstall it to the same position.

Remove the fuel bowl and main jet, making careful note where all springs and gaskets are located. (it might be a good idea to take a picture of it with your cell phone.) Using a can of carburetor cleaner, spray all the ports and jets thoroughly. Use a bristle brush to remove the heavier deposits inside the fuel bowl and outside the carburetor body.

If compressed air is available, blow out all of the ports and passageways. A can of compressed air used for electronics will do the job nicely.

Wipe all of the parts down with a clean cloth and reassemble the carburetor in the reverse order that you disassembled it in. When putting the air mixture screw back in, turn it to a soft seat and then back it off to the number of turns you took note of earlier.

Bolt the carburetor back on to the engine head and reattach the cables and other lines. Replace the fuel filter and reconnect the line to the carburetor inlet.

The last step is to put the air cleaner back on (with the new filter installed) and bolt it back into place.

The engine will take a few turns before the pump can fill the fuel bowl, but should start right up. Let the engine warm up a bit and watch for any issues, such as leaks at the connection points.

What Does An Igniter Do On A Golf Cart?

Older golf carts used a set of points and a condenser to produce the spark needed to run the engine, but the more modern carts have a solid-state ignition system. The solid-state system utilizes an internal magnetic pickup device inside the engine that sends an electrical signal down the line to the igniter.

The igniter then takes that signal and boosts it down the line to the ignition coil, and the ignition coil creates the necessary voltage to cause the spark plug to…well, spark.

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