Carburetor help needed. Any experts here?

TractorSmith · Dec 8, 2009

I just rebuilt the carburetor on my Case 480CK. It runs better, but the problem still exists. It only runs well if the choke is about half closed.
I think I might have stumbled on the problem. I just noticed that the carb is supposed to be a Marvel-Schebler TSX-936, but the tag says it is a TSX-864. Is there a jet I can change to convert it, or do I need a different carb? Any help would sure be appreciated.

Anonymous-0 · Dec 8, 2009

You need to adjust for a richer mixture, e.g. idle air closed some, main jet opened some. You need to be sure the lean mixture isn't from manifold gasket leaks or from leaks around the throttle shaft. You can use a propane torch around those potential trouble spots. No flame just spilling propane. If the engine runs smoother you have found a leak.

The book settings on the mixture adjustments are just close enough to right to let the engine run so you can tune them properly.

On a governed engine the governor will hide the effects of your adjustments unless you override the governor, or adjust for minimum throttle opening that the governor accomplishes as you improve the tuning. The main jet may need to be a little richer than maximum engine speed lightly load when you load it to get maximum power.

Gerald J.

504-1 · Dec 8, 2009

Either you have a fuel flow problem or you need to check to carburetor again,main jet is plugged.

old art · Dec 8, 2009

i found that allthem little holes in the jets look clean but the hole has varnish on the side of the hole you can't see. i use a strand of copper wire that goes through the hale easy then i flatten the wire so it gets wider than the hole and thread through the jet andturn it to scrape the varnish out of the hole the copper wire is soft enough to not damage the jet . even the holes in the sides of the long jet tube dont miss any
this has worked well for me .
old art

Anonymous-0 · Dec 9, 2009

If you don't want to send it to a shop and spend a lot of $ on it, just take it apart and clean and blow out every jet and hole you see. Every carburator ever made will eventually give that kind of trouble. I have taken them apart, blown them out without seeing the culprit in them, put them back and the tractor runs perfect. Then other times I have cleaned them good, put them back, and changed nothing. Sometimes it takes 2 or 3 tries to find the problem but you will eventually find it. More than one time can get sort of aggravating though.

200cs · Dec 9, 2009

(quoted from post at 16:03:50 12/08/09) I just rebuilt the carburetor on my Case 480CK. It runs better, but the problem still exists. It only runs well if the choke is about half closed.
I think I might have stumbled on the problem. I just noticed that the carb is supposed to be a Marvel-Schebler TSX-936, but the tag says it is a TSX-864. Is there a jet I can change to convert it, or do I need a different carb? Any help would sure be appreciated.

First, I do not know anything about that carb but I do know that float setting is very important on some carbs. If the fuel is too low in the bowl it cannot flow thru the passages it was designed to. I had a truck that it had to be perfect on or it would not run right at all. I would try taking it apart and soaking it. Blow at all the passages and re-set the float. see what happens.

TractorSmith · Dec 9, 2009

Thanks for the replies folks. I did clean it good - soaked in carb cleaner for four days - so I'm sure it's clean. I installed new kit I bought from Case dealer including gaskets, needle & seat, and throttle shaft seal. Like I said, it runs good until you open the choke, even when its fully warmed up. I've tried going to the extreme both ways with the adjustment screws. When you push the choke in it starts sputtering and dies. 200c, that is a good point on the float level. I thought it was right but I might have to check it again. I'll keep trying.

JMOR · Dec 9, 2009

(quoted from post at 13:23:29 12/09/09) Thanks for the replies folks. I did clean it good - soaked in carb cleaner for four days - so I'm sure it's clean. I installed new kit I bought from Case dealer including gaskets, needle & seat, and throttle shaft seal. Like I said, it runs good until you open the choke, even when its fully warmed up. I've tried going to the extreme both ways with the adjustment screws. When you push the choke in it starts sputtering and dies. 200c, that is a good point on the float level. I thought it was right but I might have to check it again. I'll keep trying.

f you haven't had a fine wire thru every passage/connecting path in those castings, then you can't be sure it is really clean. Most people never know all the interconnecting passages in there. Just because you blow air in one hole & it comes out one more hole, does not mean it is clean........sometimes one hole branches into two , so air in one and out another misses the 3rd.

730d se · Dec 9, 2009

From my experience, soaking a carb is fine as long as all you have is gum, vanish, etc., from old gas. However, if the carb has rust, air leaks, or has partially plugged circuits, it will never run right until you rebuild it properly.
The jets must be removed, sometimes they are stuck and the slot will break off or round out since they are brass. But, you need to get them out and then clean with a wire, soak, and use air pressure to make sure all passages are clear.
A partial choke to make it run means that it is not drawing enough gas on it's own like it should.
This can be several factors. Fuel bowl not set properly, a blockage or partial clog somewhere in the fuel system, an air leak (typically at the choke and throttle shafts), a bad gasket seal between the bowl and the upper carb, etc.
I start by making sure that I have a steady and consistant fuel flow.

Carburetor help needed. Any experts here?

TractorSmith

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Anonymous-0

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504-1

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old art

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Anonymous-0

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200cs

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JMOR

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730d se

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