Spitfire 78 spitfire running rich

[AlcoPower]

Hey guys. I have a 78 spitfire that suddenly went from 30 mpg to about 10mpg and blows black smoke out the tailpipe. the car had been running fine until it had been parked for a few weeks. i removed the carb and cleaned it up and did a rebuild on it. the car started once i reinstalled the carb but in trying to adjust it the spark plugs all got washed out. does anyone have some good advice on how to resolve this problem? single z-s with converted water to manual choke.

 

[poolboy]

I'd think the problem is either with the choke or the float chamber needle valve malfunction.

Under less suspicion would be the floats that have taken in gas
Be sure to smell the oil on your dipstick..If it has a gasoline smell, you need to change it and the filter before restarting the engine.

 

[Bruce100]

is it running rich or missing badly? A car missing badly will also create black soot from partially combusted gas. Make sure your ignition/timing didn't get messed up in the process of tinkering.

 

[sd80mac7204]

Looks like the car is missing pretty bad. or was missing pretty bad. It doesn't run now. When I saw it this weekend it had turned the bumper black. I know the floats were ok and replacing the needle valve did not change how the car ran. Maybe bad spark plugs?

 

[Bob Claffie]

I had a '76 Spitfire with that crappy carb on it. Good for about 15-16 MPG , at night it was a mobile light show, shooting flame out the tailpipe when decelerating. Actually ran pretty good in spite of everything. Never did fix it, daughter got rear-ended in it and the ins co totaled it. If at all possible switch to twin SU's. Bob

 

[AlcoPower]

4 new plugs and some tweaking today. Car runs!