"A" Carb troubles

Tue Apr 03, 2007 7:24 am

Ok I am in need of some help. I have a zenith carb on my 1945 A.
when I got the tractor I got it running and have had the same problem since day one of getting it running.
When you throatal it up it hesitates and sputters then fianly gets up to speed. Its like it is starving for fuel. I did change the plugs and wires and still need to get a new dist. cap I did gap the points to .013 becasue its a mag.
It just acts like it is starving for gas. Now I know I didn't help matters that when I took it apart I put it in the bead blaster at work after tearing it completly apart. I know lots of people frown on it but I have had good luck in the past but they were on good running carbs in the first place.
Well it looks new and I have a good clear coat on it so it wont tarnish up.
anyway what do I need to look at? It still starves for gas and I can not get it to idle any different when I screw in the idle mixture screw. Just like on all my cubs 99% of the time that screw doesn't work. Only 1 or 2 times out of pure luck I have got the carb right and that works.
I tired putting a fine wire through the passeges of the carb but could only go so far. What should I do? Also new gas and sediment bulb assembly on the tractor so that isn't a problem. I also cleaned the screen on the inlet of the carb.
anyone have suggestions?

carb problems

Tue Apr 03, 2007 9:21 am


I had the same problems last week on my cub. It has a Zenith carb. It started fluttering like it was starving for gas. Took carb off, cleaned and reassembled, set valves, new points, condenser, and coil. Still had same problem. An old tractor mechanic said that if what I had done did not cure it, to try another condenser. He said that sometimes new ones out of the box are bad. Put on another one, and it is running like a top now. Just something for you to check out.


Tue Apr 03, 2007 9:40 am

I need to do the tune up on the mag anyway I reset the points and stuff but didn't replace that yet. I will give it a try.

Tue Apr 03, 2007 10:02 am

We have a 45 BN, we had problems with the fuel line , do you have good gravity to the carb, Plus no in line filters. steel line recommended also. same
dia as cub.

Tue Apr 03, 2007 10:20 am

It is the original gas line no filters just the original set up. I suppose it could be plugged up.

Wed Apr 04, 2007 6:42 am

Last night we swaped dads Farmall A carb out for mine and it was 100% better in performance when going from idle to reving it up. Hardly any stumbiling and any that is left is probably plugs and tune up stuff.
so I guess it is back to trying to un-plug the carb passageways.
I have pushed a wire as far into things as I can get it but maybe I need to try something else.