Running Rich

[felo72]

I have a 75 Spider 124 with a 32 adfa carb. I rebuilt it recently and have been trying to get it tuned in. I think I had the jets switched at first, so I took it all apart and made sure to use the smaller sizes on the primary and the larger on the secondary. Then I noticed it's blowing fuel up through the main ventury when you first hit the throttle from idle. I checked the return line, and no fuel coming through it running or after I turn the car off. I noticed it's a really small hole, but think it could be clogged. Could it be clogged? Does fuel flow all the time through the return?

[felo72]

The return line was clogged, but it's still running really rich. I was able to get a paper clip through it. Since it was the original float, I did not adjust it. Guessing I should check that next.

[18Fiatsandcounting]

Yes, I would check the float level. But a question: how do you know it's running rich? Smell of gas, sooty plugs or exhaust, poor gas mileage, or ?

The ADFA has a number of hoses and tubing running to it, all working together (in theory) to keep the mixture correct. Other possible causes for running rich are the choke being stuck on, or the fuel pressure is too high and it's "overpowering" the float needle valve. Or the wrong jets, but I think you already looked into that.

-Bryan

[felo72]

Thanks for the reply
. I'll check the float tomorrow and report back. When I hit the throttle, it hesitates and sprays fuel up as if it's getting flooded. The throttle response is bad and the idle doesn't really smooth out unless you're at 1,000 plus rpm. Anything below and it seems like it has a cam, shaking really bad. It's all stock, so it should be smooth. I replaced the fast idle and choke diaphragms, so there shouldn't be any vacuum loss there. Besides the float, only other thing I could think is I have the jets wrong. Smallest for primary and biggest for secondary is how I set them up.

[Nut124]

When did the engine last run well? Spitting fuel up from the carb sounds like a cam timing issue.