Backfireing Golf Cart
 

I have a 2015 gas Yamaha golf cart not efi.

After running about 20 minutes it backfires when coming to a stop after going down a hill into a tunnel or approaching a red light.

I bought the cart used (remanufactured) and it is still in warranty.

I had it back for repairs 6 times and the problem still exists.

HELP

#1 cause: The throttle plate in the carb is not totally closing when you get off the gas.


Since you purchased a used cart, I'm guessing this is it.

On my 2010 Yamaha I found that the connection between the expansion chamber (muffler) and tailpipe was not air tight and would back fire. On mine the original connection hardened and shrank even though there were strap clamps.

Just had exactly the same issue...Willy’s came to fix...the hose between the muffler and the tail pipe had come off or broke. New hose, 2 clamps and problem fixed. Easy DIY fix. Had Willy do an annual while he was there.

6 times- forget warranty and take it to someone that knows carts.

we would like to know where you brought cart from ???:boom:

:ho: I find it hard to believe that a missing piece of heat resistant rubber hose would cause a backfire. Maybe :shrug:

My Yahama was backfiring after servicing which included installation of a new spark plug and when I drove it it backfired. Had it looked at and found there was almost no gap on the spark plug. He gapped it and no more back firing.

My guess is that you or someone has opened the governor to gain speed. This dumps more gas in the engine than it can process so the gas builds up in the cylinder when you take your foot off the gas resulting in explosions known as backfire. Eventually this will destroy the motor.

You have an exhaust leak.

muffler

Since it is carbureted the most likely cause is the carb itself. It sucks in too much fuel when deceling and heat fires in the exhaust.

On April 2nd 2018 an irresponsible golf cart owner that failed to maintain their golf carts changed my life forever. I was just leaving a golf cart tunnel when a golf cart came down a hill and had a tremendous backfire about two feet from my left ear. The backfire has caused permanent tinnitus (for those of you that don’t know what the is, look it up). The loud ringing in my head is 24 hours a day and the only way to get any sleep is with medication. In addition the blast caused nerve damage to my left ear as well, making it necessary for me to take pain medication to combat the pain. Be responsible and fix your dam carts before you ruin someone else’s life!!

It sounds like your accelerator cable is to tight. Coasting down the ramp your foot can not touch the accelerator pedal.when you touch the pedal it should not immediately try to start, there should be some play in the cable. If cable is too tight it pumps gas in cylinders even while coasting.

Get a new mechanic to look at it

I thought the exact same thing. I doubt that was the issue as that is an add on piece

There is most likely a problem with the throttle plate on the carburetor. It is not closing all the way when your foot is off the pedal because the throttle linkage is out of adjustment or the spring which holds the throttle plate closed is either weak, broken or missing entirely. You can check this yourself. With your cart in neutral or the rear wheels off the ground, slowly depress the pedal with your hand while watching the throttle plate shaft. The starter motor should start before you see any movement in the throttle plate shaft. If the throttle plate starts to open before the starter motor starts you have found your problem and you need to loosen your throttle linkage or replace the weak or missing spring. I had the same issue with an older (1987) EZGo. Replaced the spring with a couple of ball point pen springs meshed together. Problem fixed!

Lots of suggestion here and any of them might be the problem. I can tell you I had an older cart that backfired all the time and despite having it serviced several times the problem persisted. I eventually had the carburetor replaced and that solved the problem. Good luck.

Another problem could be a sticky intake or exhaust value in a 4 stroke engine. However if it runs ok when your driving, that would be unlikely. Definately not an exhaust pipe or muffler problem. You could replace the whole carburetor for $$ but it may just need a simple adjustment or spring replacement. Definitely wouldn't take it back to the guy you had it to six times! I've used Todd Casey golf Cart Repairs with good results. (352) 466-3934.

A very good golf car mechanic would have been able to fix it without changing the carburetor. Its very rare to ever have to change a carburetor or fuel pump on these things. Someone says you need a new carburetor- get a second opinion.

Good advice!

How fast is it going, when people monkey around with the governor trying to get them to go fast they will backfire. Also they will burn the valves up in them, just ask a golf cart mechanic.

Hopefully you didn't hear that from a golf cart mechanic, the valves are not going to burn up from a backfire.

I agree with all the posts that say you need a throttle adjustment. Unburned fuel is getting into the exhaust, which is happening because the throttle plate is not closing completely when you release the accelerator pedal. On my Yamaha at least, releasing the accelerator pedal shuts off the spark.

I'm going to assume that the backfiring is happening when you initially step on the pedal and not when you are running at speed. Again, this occurs when the throttle plate is not closing properly, or opening too early. Someone mentioned that the governor may have been adjusted too far. When that happens it allows the engine to over rev leading to a condition called "valve float". The engine is rotating so fast the valves can't keep up and this will cause some popping/backfiring as the valve timing begins to breakdown, but this occurs at top speed. Its also very hard on the engine and will eventually lead to early failure.