Ok guys ive been tinkering around with a 83 12a Rx7 for about 2 weeks now. i cant get the thing to stop sputtering out, fuel pump is good, i changed the fuel filter, rebuilt the carb, AND STILL it sputters out at about 40 mph. when i first purchased it, it did it about 55, so changed filter, ran ok for about a day then did it again but at this speed now.

Fuel filter again?

Maybe lines?

 

Its worth checking the fuel filter again. If your gas tank is rusty on the inside, it doesn't take very long for the fuel filter to clog up.

 

hey i had the same problem. it would run fine then all of a sudden it choked down. my filter was clear, and a new higher pressure pump. its probably your metal fuel line fromt he pump to the carb. put a filter bettween the fire wall that carb inline and let it run just sitting and maybe give it a little gas, then lookk at your filter, mine was brown with in minutes. hope this helps

 

Could be an ignition or grounding issue too.

Have you done the basic tuneup yet? Cap/rotor/plugs/wires will go a long way to solving/preventing issues like this. Also, make sure that the cables from the battery to the starter are in good shape and have good/clean connections.

 

Aight guys it was the fuel filter, runs very nice now, i have a few more to put on it to ensure no unexpected problems arrouse.

 

If it keeps clogging, it means theres crap in the tank.