3020 gas

[Ranhil]

Put new plugs and copper wires on my 3020 as it was running a little rough. Now it runs great when cold and or low idle, but cuts out and runs rough when warm (puffs black smoke). Is this a carb setting problem or could it me a leaking manifold gasket.

thanks
Randy

 

[Mike M]

How are your points and cond. ? your spark could be weak or just maybe carb. is running too rich ?

If you have an alum MS carb. they are hard to get working right. They like to suck fuel past a diaphram causing off idle and mid range problems.
I finally gave in and did what others told me and found a Zenith for the 4020 and rebuilt it, that really helped it out.

 

[Roger in Iowa]

Leaking manifold would cause it to run lean (too much air) and not black smoke.

Probably diaphram in carb. I rebuilt my carb 20 years ago and no problems. Did not change to other style.

 

[Anonymous-0]

Black smoke is running rich. First thing to replace is the float needle and seat in the carburetor. Check to be sure the float floats. It wears from vibration and doesn't shut off. After that it depends on whether its a Zenith or a MS carburetor. The MS is hardest to fix and adjust. Many toss it and mount a Zenith (to the point there probably aren't any salvage yard used Zeniths anywhere but there are new Zenith available).

Gerald J.

 

[Ranhil]

I am at work and not positive, but I believe it has a Zenith carb on it. Thanks for the suggestions. I am thinking the carb settings are in my manual, but any suggestions on where they should be set?

thanks again,

 

[Ranhil]

I am at work and not positive, but I believe it has a Zenith carb on it. Thanks for the suggestions. I am thinking the carb settings are in my manual, but any suggestions on where they should be set?

thanks again,

 

[Anonymous-0]

You have it running. That's all the manual settings are for. Now you refine it until it runs right. With the black smoke its running rich. Fix the float needle and seat first, then lean the main jet or add more air to the idle jet depending on which is running rich. If both are running rich, I bet on the leaking float valve. Been there fixed that, didn't have to tweak my 4020 anymore.

Gerald J.