Fine Tuning....

[pferguson1962]

I have this '47 Cub running (sort of) after many months of a rebuild and am having trouble getting it fine tuned so that it runs smooth. The carb is clean and i have an inline filter just in case it has trash from the tank. I can start it with the choke set at about 3/4 closed. It runs roughly for about 2-3 min and it dies as I attempt to open the choke ever so slightly.
Not sure what is going on but it seems as though it is not getting enough gas. I have noticed that it seems to be leaking air around the float bowl gasket. I tried tightening the screws but no change. I have another gasket ordered and on the way but I thought I'd ask you guys to see if there is something else I need to be lookiing at or if you can provide tips to fine tune this tractor.
I read an article somewhere a couple months ago about the tops of the original IH carbs getting warped and how to straighten them. I think mine might be one of the warped ones. I'll see if the new gasket helps before doing anything drastic.

I welcome any advice or suggestions.
Paul

[ScottyD'sdad]

Most likely a warped top. Many of us are able to straighten the tops. There are posts on how it is done. or, you can PM Cecil. or some others. Often can be done at a cubfest, if any are near you. Could als be fuel flow, restricted by the filter, opr a partially bloocvke main jet. (Brass hex head, on the side. Remove it, poke it with a thin wire, blow it out, and reinstall.
Ed

[Papa's Cub]

Paul, I'm experiencing the same problem with my 76 cub. I have to choke it to get it started and it will only run smooth with 1/2 choke. Even after it warms up a bit, I can't push the choke to normal with out it spitting and sputtering to a halt. Years ago I remember the "back yard" mechanics would squirt oil at the base of the carb and intake manifold gaskets trying to find an air leak. Since this is an easy test I think I'll try this on my cub. ( a simple vacuum test would work too ) Let us know the trouble shooting procedure you use to resolve your issue. Good Luck, Tom.