X380 backfires

[149owner]

My X380 with a 23hp Kawasaki engine has developed a problem of backfiring through the exhaust with the engine speed varying when throttle is set and not being moved. At first I thought I had put bad gas in it so I drained and refilled it with fresh gas. Then I found the air cleaner was plugged up with grass so I put a new air cleaner with a new outer foam filter in it. If I let it cool down and restart it, it will run fine for about 5 minutes and then starts to backfire through the exhaust and the engine speed will begin to vary (hunt). Should I remove and clean out the carburetor next? TIA

 

[Gator6x4]

My X380 with a 23hp Kawasaki engine has developed a problem of backfiring through the exhaust with the engine speed varying when throttle is set and not being moved. At first I thought I had put bad gas in it so I drained and refilled it with fresh gas. Then I found the air cleaner was plugged up with grass so I put a new air cleaner with a new outer foam filter in it. If I let it cool down and restart it, it will run fine for about 5 minutes and then starts to backfire through the exhaust and the engine speed will begin to vary (hunt). Should I remove and clean out the carburetor next? TIA

Some things to consider:

First:
“Check for intake leak first. Some Kawasaki engines are prone to intake gaskets leaking. Spray fluid where the intake mounts to cylinder head on both sides while it's running .


1. Fuel System Issues:

• “Lean or Rich Air/Fuel Mixture:
  .
  “An incorrect balance of fuel and air can lead to incomplete combustion, causing backfiring. This can be due to a clogged carburetor, a faulty fuel pump, or issues with the fuel lines.
  
  
• Carburetor Problems:
  .
  A dirty or improperly adjusted carburetor can disrupt the fuel-air mixture. Check for clogged jets or a distorted o-ring gasket.
  
  
• Fuel Pump:
  .
  A failing fuel pump may not deliver fuel at the correct rate, impacting the mixture.
  

2. Ignition System Issues:

• Spark Plug:
  .
  A fouled, damaged, or improperly gapped spark plug can produce a weak spark, causing incomplete combustion and backfire.
  
  
• Ignition Timing:
  .
  Issues with the ignition timing, potentially due to a damaged flywheel key or coil, can cause the spark to occur at the wrong moment, resulting in backfiring.
  
  
• Ignition Coils:
  .
  A weak or failing ignition coil can produce a weak spark, leading to backfiring.
  

3. Other Potential Causes:

• Valve Problems:
  .
  Valves that are not seating properly or are misadjusted can cause backfiring, especially during throttle transitions.
  
  
• Air Filter:
  .
  A clogged air filter can restrict airflow, impacting the fuel-air mixture and potentially causing backfiring.
  
  
• Fuel Tank Vent:
  .
  A blocked fuel tank vent can create a vacuum, affecting fuel delivery and causing backfiring. “

 

[oldnslo]

Try easy thing first and change spark plugs. Possible that they are carboned up from running rich due to plugged air filter.

Engine speed varying or hunting usually indicates a fuel to air ratio problem. Does your X380 have manual choke independent of throttle? If yes try slowly closing the choke to see if engine runs smoother. If yes then need to check for intake leaks or clean the carb.

 

[tomplum]

So, surging etc. after it has run for 5 minutes? A real simple thing to try is get a few feet of 1/4" fuel line. Drop one end into a small fuel can and the other hook behind the fuel filter. If it doesn't do it, debris is plugging the pick up in the fuel tank.