Black Spark plugs

[Mark]

The only reason I can think why the plugs were black is too rich a mixture so the jets are too big, but I thought I checked that out too. But a good while ago I went thru the setting the idle mixture screw, etc.The mutt runs good, when just depressing the foot feed down there is no black smoke, when I tromp on it, then I get black smoke out the exhaust which I thought was the accelerator squirting the stream of gas into the barrel of the carburetor, holly carburator it is.
I could have asked this before, but my memory says no.I went thru the mixture screw setting bit a good while ago.I may have also asked about the jet size.Had a problem with mixture screw vibrating loose then, I put lock tight on it.That is holding the screw in place.Ya, the float level checked out good then too.Surely the fuel pump pressure is not too high(could be though)Nobody has exhaust gas analyzers anymore.I guess I could put the zenith carburetor on the mutt.It ran good when I bought the A2.The needle might have a ring on now??So if I put it on, it still could have black smoke out the exhaust
I bet the repetitious same questions get exasperating.
If the float level, float, /checks are good then there should be no black spark plugs.The air cleaner paper filter shows light thru it good.I guess I'll try shooting air thru it to see what that feels like(both ways) or I'll remove it to see if that has an effect?
Then I also got a more urgent personal problem--I am getting a fat belly over the belt condition!!
Remember we live in the best country in the world so have a good 4th!

[rickf]

Unless you went way far out of your way to find and change the jets then what was in that carb are what should be there. What altitude are you at? If you are above 10,000 feet I can see where you might have a jetting issue but there is not much you can change that will help. Changing the main jet is not really going to help unless you are running highway speeds all the time. Running around town you are getting more of a reading from the mixture screw due to transition readings. Try leaning out the idle mixture.

[Mark]

The elevation is 1473, I cleaned the plugs with the old wire wheel method.I guess I'll do some 50 mph driving for a hour or two then look at the plugs color.
Thanks for the feedback.

[Mark]

The mutt had a paper air filter, I could see light thru it, so I always thought it was good.But I thought it's the last factor that could cause too rich a mixture, I tried blowing air thru it, nope, no air thru.So I found a old mesh air filter, added oil(2.5 pints,30wt).No more black smoke.Of course the mutt now seems to have better acceleration.No black exhaust smoke, even when flooring the foot feed.So once again, I think I found the cause/solution?