Carb float setting - Case SC

booger1945 · Mar 5, 2023

I have a Case SC that has been a project tractor and is now about 98% complete. I rebuilt the carb and set the float to the specs in the kit (don't remember the dimension). For some timeI have been suspicious the the float is set too low, as when I shut off the fuel at the sediment filter, the engine stops nearly immediately, like there is no reserve in the carb. Yesterday it stalled on me on a incline, and won't fire off. It acts like it's not getting fuel. I plan to re-adjust the float and try again, but would like opinions from those of you who may have had a similar experience. The reason I have not already raised the float is that it when the engine is not running, there tends to be a small fuel drip from the carb air inlet, if the fuel line is not shut off. This makes me think the float is already too high.
Any suggestions?
Thanks, booger 1945

Steve@Advance · Mar 5, 2023

If you went back with the old float, there will be a 'water line' imprint where the gas has stained the metal. Get that parallel with the top when inverted and it will be real close.

If it's a new float then go by the specs, usually a measurement between the top of the float and the bottom of the cover gasket when inverted.

The float drop should be sufficient to let the needle valve open but not pull out so far that it can come out or cock, it's not a real critical adjustment.

Another test is to turn the top upside down, let the float rest on the needle, suck on the inlet fitting, put your tongue over the hole. It should hold vacuum.

Realize the incoming fuel must be clean! The slightest piece of trash will foul the needle valve. I like to do a final flush of the line before connecting, You can even let some gas flow as you make the connection if the area is dirty.

rustred · Mar 5, 2023

sounds like the gas is tricking in the carb just enough to keep it running. check the flow at fuel line before carb. should be running a full stream plus the fuller the tank the better the flow. i high float keeps more fuel in the bowl not less as your thinking. turn the top half upside down and if the float is sitting level it is GOOD. plus u must make sure the needle is seating as that is what it appears is happening in the leak. you said u set it to factory spec's so it must be sitting level now. float level means float level.

JustIn Case · Mar 5, 2023

Dont know how this compares to Rochester carb on a Mercruiser. Years ago seat in carb got loose, vibrated down making needle and seat close sooner. I had been into carb and apparently didnt get seat tight enough. Jim

504 · Mar 5, 2023

First is take out the needle valve and polish the three sides,it is too big and is hanging up in the seat, very common in carb parts from the land of almost right. Fine emery cloth on a flat surface and slide the needle across it ,the high sides not the low sides. The way I set the float is turn the body upside down and the float should be parallel to the body

chuck machinist · Mar 5, 2023

X-2 on that solution. It drove me nuts for 3 days on My DC-4 CM

booger1945 · Mar 5, 2023

Thank you!

Carb float setting - Case SC

booger1945

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Steve@Advance

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rustred

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JustIn Case

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504

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chuck machinist

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booger1945

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