I replaced the original carb with a Weber 45 Dcoe carb and side draft intake. We were told to wire the omp all the way open but when we would stop the car and turn the engine off oil continued to be sucked into the engine coating the spark plugs causing them to foul out. The next time you turn the engine over the car would idle but when driven would really start to misfire and it would become almost impossible to drive. We did several tests with new spark plugs and each time we sand blasted an old set or put a new set in, it would run with out a problem. The distributor and the rotor are fine as are the wires. We have now closed the omp and are running premix gas and 2cycle oil but now even with new spark plugs, it is still misfiring.

Does anyone know what could be wrong?

 

This has nothing to do with the MOP or the premix oil. Your fouling out because the
carb is running too rich. You need to figure out why. It could be a couple of things:

1. Fuel pump pressure is too high. I think it needs to be around 4 psi for Weber.

2. Floats are set wrong. I wouldn't fool with this one until the last resort.

3. Your idle air bleeds need to be adjusted. At idle and cruise these affect the
mixture the most.

4. Needle valve is sticking open.

So is the carb recently cleaned or rebuilt or brand new? If not it may need a good
cleaning and maybe a rebuild replacing all the soft gaskets at least.

 

The carb is brand new. I haven't not adjusted anything but the needle valve. I only have the stock fuel pump. I don't know what that runs at. How do you adjust the idle air bleed?

 

just because the carb is brand new doesnt mean its jetted correctly. get a weber tuning manual and get to work. it also sounds like you need a haynes manual for the car. and go download the FSMs at foxed.ca

 

Okay so I replaced the Etubes and the main jets. I went from F7 tubes to F11s and from a 160 mains to 180 mains. The car runs great now.