Engine backfires around 2500 rpm

[Sarnia]

Engine backfires around 2500 rpm and sometimes when you first takeoff
any suggestions (2001 4.3 litre mercruiser)
thankyou

 

[dubs283]

any suggestions (2001 4.3 litre mercruiser)

Check for a lean condition, fuel filter(s), fuel pump pressure/vacuum, incorrect timing, ignition system components old/failing

 

[Sarnia]

Ok thanks will start checking above, appreciate the reply

 

[Bondo]

Ok thanks will start checking above, appreciate the reply

Ayuh,.... Welcome Aboard,...... Check the Contents of the fuel filter, for anything but clean fresh gasoline,.....
Don't just pull it, 'n toss it,......
You'll miss a Great diagnostic point,....

 

[alldodge]

Either way its a fuel issue and most likely a carb problem. Backfire at 2500 is lean so carb not supplying enough fuel. Causes; dirty carb, weak fuel pump, antisiphone valve

Backfire on take off is lean fuel. Causes; dirty carb, carb accelerator pump

 

[jimmbo]

Could also be a crossfire from Spark Plug Wires or Distributor Cap. Acceleration increases the Voltage required to fire the Plug and Electricity doesn't where it goes, as long as it can complete the Circuit.

 

[Sarnia]

Could also be a crossfire from Spark Plug Wires or Distributor Cap. Acceleration increases the Voltage required to fire the Plug and Electricity doesn't where it goes, as long as it can complete the Circuit.

I have a 2001 4.3. Was doing same thing , replaced wires, filters, s plugs, coil, was still backfiring , turned out to be faulty thermostat changed it and boat runs like a top.