I have a Walbro carburetor off a single cylinder 12.5 HP Briggs and Stratton engine Mod 289707, Type 0179. Carb has the numbers 41 in raised lettering just above and to the left of where it says Walbro. Walbro and 41 are on the side of the carb which faces the engine block when mounted. It does not have an adjustable fast idle screw. The riding lawn mower is Poulan Pro/Weedeater with 38 inch cutting deck. I read information on how to remove the brass seat of the carb, which I have not yet done. The problem I am having is that it appears that the needle is not seating properly while sitting still and not running. This was a prexisting condition of the mower when I bought it. I took the carb off, cleaned it, and reinstalled. It sat for two days, no flooding. On this particular carb/intake set up, the breather intake tube is attached to a point before and just above the carb bowl and before the venturi. When the bowl floods, gas runs thru the breather tube, into the breather, and into the engine. <BR><BR>I can start and drive the RLM around and mow just fine, no problems while it is running, it is not running rich. However, after I park and turn it off, after a while, gas leaks slowly out of the breather intake tube. It acts like the needle is not seating properly, as gas will slowly drip/seep out of the breather tube connector. I disconnected the breather tube to prevent gas from entering the engine. It's not a quick flood, just a slow annoying type of seep. I thought debris might be the problem, that is why I cleaned it. When I turn the carb upside down, the bowl actually sits below level. e.g. the end of the bowl opposite the pivot point sits below level. There is no way to adjust the bowl to level. The float is plastic and I have checked it for leaks. I have even replaced the float with one from another carb that does not have this problem, and still, problem persists. I've purchased and installed a new needle, problem persists. At this time, I want to learn how to replace the brass seat. I read how to remove the brass seat via a different thread on this forum. How do I install the new brass seat?. And if I install a new brass seat, will this cure my problem? P.S. How come you guys don't have a smiley of a guy banging his head against a wall? It would be so appropriate to me. Thanks in advance for any information you may have to help me end my woes.