The problem: Gas leaking out of carb while engine is not running. Gas trickling from ports on either side of the Valve Choke (#108).





What I've done so far: Removed air filter, float bowl, carb float, valve needle and seat. Checked for obstructions, none but cleaned it anyway. Replaced all parts. Reattached gas line. Once the float bowl fills up, gas continues to pour out of the two ports. When I first disassembled, the needle seat pretty much fell out. When I reassembled, I pushed it up as far as it could go. Wondering if I pushed it up too far, I installed the needle and the carb float. Leaving the float bowl off, I reattached the gas line. Without applying upward pressure to the carb bowl, gas flows down the needle, as it should.





When I apply light upward pressure on the carb float, I can feel the needle seat itself up against the seat, when that happens the gas stops flowing. So I assume its working ok. I reassemble everything and start the mower. After priming itself, it chugs to a start then works ok. Ran for about 1 min. No leaks. I leave the mower and come back 30 minutes later and gas is again pouring out of the carb, from the two ports on either side of the Value Choke. Definitely out of the port on the left, and seemingly out of the right port too.

Question: What could be the problem? I don't know much about small engines other than knowing the problem has to be air, gas or spark. It gets air, fresh gas and a new spark plug was bought to eliminate that issue.

Thanks for your help in advance.

Jim

I tried your suggestion. Put it all back together and started up the mower, ran for 30 secs, stopped it. Then sat back to stare at the carb to see if it would leak. Waited a few minutes, no leak. Thinking that "maybe" I was successful, I pushed the mower across the driveway (crushed stone) to the storage shed. By the time I got to the storage shed, teh carb was leaking gas.

Back to square one. :(

Jim

Jerry

Thanks for that.Yes it is a briggs motor, 6.75hp. You're the first one to mention the viton seat having a groove. Everybody else I spoke with (outside this forum) thought the grooves were the problem. The needle and seat look brand new, no build up, no corrison, no cracks upon closer inspection with magnifying glass. Yesterday I had a devil of a time getting it to continue running. When I could get it started, I'd have to remove the entire air filter apparatus. Once it ran, I could put everything back on. As soon as I started walking down a slope on the lawn (+30 deg) the engine died. Took it all apart again and discovered the seat had turned partial around in its position so it wasn't sealing at all. Straightened that out and tried again. This time the mower worked ok. My frustration level was quite high at that time. I was ready to let it roll down the hill into the forest below. =8-#

Jim

Jim

Jerry