installing a zenith on an early cub??

Thu Jun 27, 2013 3:50 pm

can it be done? would i notice any more power without any aditional modifications? i know that later cubs have other changes are well, but would that alone make a difference? did IH make any additonal changes to the C60 that would make the zenith incompatable with the older tractors from the 40's and early 50's? when was that change in carbs made anyhow?

Re: installing a zenith on an early cub??

Thu Jun 27, 2013 4:22 pm

Yes. Not likely. Not likely. No. 1975. :D

Without other modifications, you're not likely to notice any difference by just swapping carburetors. You'll see more of a difference from a proper tune-up and valve adjustment.

Re: installing a zenith on an early cub??

Thu Jun 27, 2013 5:54 pm

Ditto to what Don said. To take it even further, I've seen carbs on cubs that weren't even cub carbs.

Re: installing a zenith on an early cub??

Thu Jun 27, 2013 8:33 pm

I just put one on my 1950, installation is easy. I am having a little trouble getting it working properly but I think it will be better in the long run. I think it has more power, not a whole lot more. I went by the advice of a couple of people that know far more than I, they recommended it highly. I have never had a good working IH to compare it to.

If I did it again, I would buy a used one and have it rebuilt, rather than buy new. PM me if you would like more info.

Re: installing a zenith on an early cub??

Thu Jun 27, 2013 9:47 pm

Hopefully someone more knowledgable will come along to clarify this, but I do believe there are two different exhaust manifolds, one to allow for the larger throttle valve plate diameter of the Zenith vs the IH Carb. If the opening on the bottom of the exhaust is the small hole I believe it can be ground to a bevel to add the additional clearance needed.

Re: installing a zenith on an early cub??

Thu Jun 27, 2013 10:21 pm

I have one on my '48. The flange on the top of the carb is definitely larger than the flange on the bottom of the manifold.

Re: installing a zenith on an early cub??

Fri Jun 28, 2013 8:40 am

Dale Finch wrote:Hopefully someone more knowledgable will come along to clarify this, but I do believe there are two different exhaust manifolds, one to allow for the larger throttle valve plate diameter of the Zenith vs the IH Carb. If the opening on the bottom of the exhaust is the small hole I believe it can be ground to a bevel to add the additional clearance needed.


The bore on the zenith is larger than the IH, the intake manifold can be beveled or 2 gaskets can be used to provide proper clearance for the butterfly, otherwise it can be bent. The intake side is also larger so an adapter is required on the intake / air cleaner side.

This information was provided by folks far better qualified than I.

Re: installing a zenith on an early cub??

Fri Jun 28, 2013 9:10 am

tmays wrote:Ditto to what Don said. To take it even further, I've seen carbs on cubs that weren't even cub carbs.

That's right. George Willer had a Briggs & Stratton carb on a Cub.

Re: installing a zenith on an early cub??

Fri Jun 28, 2013 9:57 am

I don't know what you have for a Cub, but from a 40's Cub to a version from the Factory with a Zenith carb, there was a different cam, different governor weights, higher compression pistons, and a larger intake manifold. A "bigger" carb on a tired motor will do nothing but make you feel better and make your wallet lighter. None of the above changes turned the Cub into a Super A. That said, the 1950 motor I am building will have pop up pistons, the later manifold, the later camshaft and the later governor when I stumble upon one. I am going to use the IH carb because that is what I have and it works just fine on my 74 that has everything listed above except the manifold. Good compression and properly adjusted valves will work wonders and one of those will only cost you a little time and effort.