Correct Yf 938sd Float Setting ?

I have an issue with Tonka's running rich and it's been getting worse; in fact I can now start & idle with the the throttle completely closed (idle speed screw not touching the stop) & the idle air screwed all the way in . It runs rough but it runs & does a great job of fumigating the garage. If I take the idle air screw out it perks right up & idles normally.

I've torn the carb down, not finding anything obvious like a leaky accelerator pump (diaphragm is getting iffy but not lleaking yet- replacement on order). The idle & main jets are, to the best of my ability to measure them, at the very least pretty darn close to the sizes listed in BrianP's posting on the subject some years ago-

http://www.earlycj5.com/xf_cj5/index.php?threads/51842/#post-578329​

I've verified that the rod that was in the carb is labelled 75-1500 but the sizes I'm measuring are .079, .072, .062, .046 which, given the sizes listed as stock and Brian's own measurements, would seem to indicate I should be running leaner than would be expected. A replacement rod that I found in a 10-15 year old rebuild kit measures the same.

Moving on the the float & valve i do have the correct spring loaded needle. The float was Not at the 5/16", 5/16" listed in the manual, it was actually a bit wider which would have the effect of lowering the fuel level in the bowl, again I would expect this to lean things out a bit. However looking at a carter adjustment bulletin I found over on the 3B page

https://cj3b.info/Photos/Tech/Carter/YF1961p1.gif​

I saw something I haven't seen before- for "resilient seat" valves the cover-float setting goes up to 1/2". Now my valve has the rubber tip- is this the same thing as a "resilient seat"? At 1/2' the float sits a lot closer to how the illustration in the manual looks-

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5/16" setting-

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1/2"-

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What I'm thinking is that the 5/16" setting is too high making things run rich, although I have no explanation on why its been getting worse as the float is not leaking.

So I guess my question is can anyone inform me on the proper float setting, and is there anything other than the float that I've missed ?

 

I have a numbered set but the right size for the main jet is missing, a 3/16" is pretty close & felt about right for the fit. For the idle jet my set doesn't have any bits that small- I used a piece of wire about the right size, again it felt about right.

 

Ahhh- yes iIdid do that

 

It's definitely not a shaft leak. it may be that the carb was not bolted down as tight as it should have been- the nut next to the valve cover was , if not exactly loose, not exactly tight..

I'm not understanding why an air leak would cause the rich condition- more air should lean things out at the cylinders should it not?

 

That nut is in an awkward place which makes it hard to determine if it's tight enough or equally tight to the other one.

 

It was 18-19" last time I checked it back in early July. Little hard to check now as the carb is in many pieces but it was also running rich then.

Got the rest of those notes handy??? (?)

 

The carb is in brand new shape- this is one of those carbs that the guy in Turkey was selling a few years back.

When I get the new pump I'll reassemble & adjust everything with the floats at the the 1/2" setting- we'll see how that works.

 

I wonder if the rubber tip is porous?

 

Could be, I have a new valve that's going in.