Cub 184 running lean

Charlie M

Well-known Member
My IH Cub 184 tractor has a problem that sounds to me like its running too lean all this year regardless of what I have tried to do to fix it. It will run pretty good with the choke part way on is why I'm saying running lean and there is no smoke when I do it. I've done the stuff that I know causes that - cleaned the carb and looked for leaks. I thought I had found a leak in the manifold gasket and changed it but didn't fix anything. Concerning the carb I have had it off several times and was able to get a wire through and spray carb cleaner through every passage. Carb looked good first time I took it off. Its a Zenith carb. I have a good flow of gas to it. Float level is set per I&T manual - can't remember exact number. Valve clearance is set by the I&T manual and I rechecked it to be sure. I just had some oil on the breaker points and cleaned them so I know they are good for now. I hope someone has some other ideas as I am out of ideas.
 
Double check the point gap and also you might try to adjust the timing a bit. I did that to my cub and it sure did help
 
I did that today. Because the mower makes it hard to work on the points I end up pulling the distributor to do anything with points and then I have to check timing when I'm done.
 

The zenith carb has the main jet under the plug in the bottom of the bowl. Unscrew the jet and clean it. I bet the whole is partially plugged. You did check flow to the bowl by pulling that plug and turning on the fuel, right? Just asking.
 

Make sure you have good flow into the bowl. Running better with choke is almost always a fuel problem. Leave the plug out and turn on the fuel. Should be a steady stream like pencil size or a little smaller. Let us know.
 

Have you checked the level in the bowl with a clear tube? Level should be 9/16-5/8" below top of the gasket. If your floats aren't adjusted and your level is low, a lean condition could result. Is your throttle shaft worn to the point an air leak has occurred? Warped carb top? Definitely either fuel or an air leak.

Good luck
 
Thanks for trying to help me with this - another question. How do you check the fuel level with a clear hose? I've adjusted the float level to the value given in the I&T manual. I could try raising the float a
little higher. If the throttle shaft is worn or the bowl wrapped wouldn't that show up when I've done a leak check.
 

Put in a hose barb where the plug goes, and put a clearish tube on the barb and have it turn straight up. Turn on the fuel, and the float will stop the fuel and you will see how high it is in the tube.

Good luck.
Larry
 
That's simple enough - I'm almost embarrassed to not know that. I'll give it a try and see what happens.
 
(quoted from post at 08:58:59 08/08/22) That's simple enough - I'm almost embarrassed to not know that. I'll give it a try and see what happens.

Nothing to be embarrased about. We all sometimes overlook the simplest things. You will solve this problem.
 
I do not know if you checked the flow out of the carb bowl or the fuel line. You do know that there is a fine screen inside the carb end of the elbow that the fuel line connects to on the carb that can plug? See number 2 in the link. The clear hose would show you it is dropping the fuel level if it is plugged. But why go through that if you can ..nip it in the bud.. so to speak.
CNHI Cub 184 parts diagram
 
you still have some dirt in the carb even though you can jus a wire thru but derbis will be built up at the bottom use a mag lite look down and you can see stuff there i use numpered drill bits and turning by hand and removing bit you will see stuff on the bit
 

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