I rebuilt my 1948 Cub IH carb about 6 months ago and it's been working fine up to now. Problem is flooding after attempted start or after started and turned off. Fuel is leaking out of a fixed plug insert, on the choak end of the carb, underneath the choak tunnel for lack of a better term. This is not the brass screw in plug farther back on the same casting. Took it apart again, float is working, can blow air through fuel inlet fine, can close the float and the air is cut off completely. The little brass lever under the float tab moves mostly freely when I move the float up and down, sometimes it sticks in the up position for a few seconds. I can let the carb drain and dry out over time, so it's not leaking from the plug, turn the gas value back open on the sediment bowl and the carb will not leak until I try to start it. Have not changed any of the adjustment screws since the original overhaul.
Anybody got a clue here what I'm doing wrong?
Thanks
RJ
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IH Carb Problems
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Re: IH Carb Problems
Check to make sure the choke lever isn't slipping on the shaft. Take off the air intake hose and watch the butterfly as you move the choke lever. Did you check the float for leaks? Immerse in hot water and look for a stream of bubbles.
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- MiCarl
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1944 Farmall H
1948 Farmall Cub (SOLD)
1994 Speedex 1631 - Circle of Safety: Y
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Re: IH Carb Problems
Updraft carburetors have that drain where you're dripping fuel to drain off fuel that condenses in the intake manifold. While it will also leak there if you have a float problem it's not unusual for fuel to drip on any fail to start condition, particularly if you're using the choke.
Since it's not leaking until you crank the engine I suspect the problem isn't with the float or needle. Check the choke as Bob says then start looking for non fuel system problems (spark plugs, ignition system, timing, compression etc.).
Since it's not leaking until you crank the engine I suspect the problem isn't with the float or needle. Check the choke as Bob says then start looking for non fuel system problems (spark plugs, ignition system, timing, compression etc.).
1944 Farmall H
1948 Farmall Cub
1994 Speedex 1631
1948 Farmall Cub
1994 Speedex 1631
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Re: IH Carb Problems
Will check the float for leaks. Just had the mag rebuilt professionally, did the line of the mark on the crankcase after the first click, set the rotor to top and installed. Move mag up against the block, crank engine around again waiting for two clicks this time. Mark was off about 2 inches. Moved the mark back to line up with the pointer then back to the mag. to move it away from the block, was suppose to click but mine didn't. Set up everything else and tried to start but failed. Gave up and just moved to TDC, pointed the rotor to just before number 1, reset and it started right up. Ran a little rough and then died. Fuel leaking out of the carb, failed to restart. Spark plugs are new, compression is 90 - 100 - 95 - 100. I did find where the choke lever had moved on the connecting rod, pushed in full was full choke, pulled out was full open. I fixed that and reinstalled, failed to start. Carb has never leaked before in the various testing and runs to check problems fixed, I know because I park it in the garage, and I watch the floor for oil and hyd leaks. Does any of this help analize?
RJ
RJ
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Re: IH Carb Problems
The rotor, in the mag, must be timed according to the timing marks. If you moved the rotor off that setting, you just tried to put a band aid on the real problem. I believe your governor is 1 tooth out of time. Re-align your rotor timing marks and repeat the process, if it still snap when rolled away from the engine block, re-time your governor.
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Re: IH Carb Problems
Thank you guys, never a dull moment with this hobby
RJ
RJ
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Re: IH Carb Problems
Hi,
Below is a pic of how the magneto drive should be turned when the engine is at number 1 cylinder TDC.
Below is a pic of how the magneto drive should be turned when the engine is at number 1 cylinder TDC.
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- Team Cub Mentor
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53 Cockshutt 20 restored (Shooter)
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49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
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Kubota B8200HST-D - Circle of Safety: Y
- Location: OH West Mansfield
Re: IH Carb Problems
I meant to say: still will not snap when rolled away from the engine block, sorry bout that!
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