Carb. Flooding

Old 10-04-01, 02:30 PM
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I recently removed a carb.(Mikuni B181AA) from a 5.5 BS Vangard engine. It was running lean and would only run with the choke on. I found some sediment in the bowl and decided to blow out the main jet. After doing so I now have flooding from the carb with only gravity feed from the tank. I have checked the float level and needle(looks fine) I have ordered a new needle but it has been backordered. QUESTION, could I have done some damage by blowing out the main jet, that Is allowing gas to flow?Is there a check ball that I could have lost? Bench testing seems to show that the needle is sealing. I am stumped on this one.
Thanks in advance,Larry
Old 10-06-01, 01:43 PM
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Hello Larry

Try floating the float in a small bowl of fuel. The float may have a hole on it. Be sure the float is level to the rim part of the body of the carb.

Try looking at the needles seat. It may have a pitt mark which will not allow the needle to fully seat.

Remove the carb bowl and attach a piece of fuel hose to the carb. Apply a breathe of air likely to the other end of the hose while gently holding the float up so the needle is seated. No air should pass through the carb. If air passes through, the neddle and or seat are damaged or incorrectly installed.

You mentioned blowing out the main jet. Compressed air is much too powerful and it may have caused damage. About the only pressure needed is that of a can of compressed carb cleaner.

There may also be damage done to a welch plug, a port or fuel passage, fuel pickup tube, fuel adjustment needle or seat. Lots depends upon where you applied the compressed air and to which fuel ports got effected by the prsessure. A lost part is always a possibility.

Close inspection is needed to verify what may have happened if you used compressed air from an air compressor.

If you plan to keep the engine on whatever machinery it is used to operate, it would be worth the price to purchase a repair manual.

Regards and Good Luck,
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Old 10-07-01, 11:27 PM
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got it

Thanks Tom,

I decided to try one more time. I was certain the needle and seat were fine, tested with hose,checked float...
So using a sewing needle I was poking and proding all the carb body castings, found the bowl vent opening and was able to clean out some type of blockage. I must have packed in with air. Carb holds gas and runs fine. Let the log splitting begin.
Thanks again,Larry

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