Farmall Cub carb hunting

old · Nov 13, 2015

So I fired up a friends cub today. It is one of the old red ones say a 1950 or so. It would sit and surge/hunt till I grabbed the carb/gov linkage and held it in one place for a couple minutes then it ran just fine. So what the heck is up with this??

kub6040 · Nov 13, 2015

Governor , or fuel , try pulling the choke some instead of the carberator linkage . Also may check the timing, cubs or my experience has been they wear bushings similar to the c113 - 153 engines and get neglected at overhaul.

DGinVT · Nov 14, 2015

This happened on my 1948 Cub as well. Make sure that your manifold nuts are tight, check manifold to block faces and gasket. also check the Carburetor to manifold faces and make sure those nuts are tight as well. I use a manifold vacuum gage to check engine performance. I also replace the IH carburetor with a Zenith -- made all the difference in the world. Have not had to adjust the replacement since. None of that control linkage should have any "lost motion".

old · Nov 14, 2015

Pulling the choke is the first thing I tried and it did not help or hurt the problem but after I grabbed that rod and held it for a moment it was just fine

rhtx55 · Nov 14, 2015

The governor is what is causing the surging, not the carb. First thing to check is the linkage from the governor to carb, they get gummed up & tend to stick. Be positively sure it is lined up when re-assembling.
Second thing would be to check & possibly replace the governor springs, drill & re-bush their elongated mounting holes in the weight brackets.
Third would be to replace the bearings in the governor, and to resurface the flange on where the flyweights ride on the main shaft using 400 grit sand paper a piece of glass on a tabletop.

Farmall Cub carb hunting

old

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kub6040

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DGinVT

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old

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rhtx55

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