Backfire

[Derky540]

Hey guys im new here. I have a 2007 mariha sx19 with a 4.3 tks. I installed a new engine. It backfires at 1800rpms through the carb and the exhaust. I have done the following.
checked timing (multiple times)
new plugs
cleaned carb
new wires cap and button
it won’t rev past 1800 and backfires really bad any help would be appreciated. Thanks

 

[Bondo]

I installed a new engine.

Ayuh,...... Welcome Aboard,..... I believe it's runnin' outa gas,......

Examine the Contents of the fuel filter for clues,......

Hook a remote tank of fresh clean gas to the fuel filter, to test the fuel pump,.....

'n what killed the ole motor,..??..??

 

[alldodge]

What is your serial number?

 

[Derky540]

I’ll grab the seriel numbers. I’m not sure it threw a rod through the block. I bought it with a blown engine.

 

[alldodge]

If unable to find the SN we can make due, its just the number lets us know exactly how the motor was built

Agree with Bondo, the backfire is running out of gas, so it could be your fuel pump is going out or there is a restriction from tank to pump

 

[nola mike]

Recheck plug wire order esp if you were messing with them.

 

[Bondo]

I’ll grab the seriel numbers. I’m not sure it threw a rod through the block. I bought it with a blown engine.

Ayuh,...... Probably from detonation, caused by a lean condition,.....

Don't do the same thing to the new motor,......

 

[Derky540]

I’ve checked the wires a few times I will check fuel filter and fuel pump pressure