Any small engine pros here? Got a question.

[Quinten]

My 11.5 hp Briggs has run flawlessly for about 8 years. All of a sudden, the rpm started surging with intermittent backfiring. I narrowed it down to a fuel problem and proceeded to remove the carb. Well, after taking the bowl off and doing the carb cleaner and air compressor deal on it, I noticed a very clean hole near the air/fuel mixture adjustment screw. I saw some residual epoxy or something around it, it did not look right. After a little research, it appears there is supposed to be some sort of welch plug in there. I did find the welch plug as it's own part, but not knowing for sure how to install it, I spent $80.00 on a new carb. So, does anybody know if this sounds right? Have others seen this welch plug fall out after several years? It certainly looks like this would cause my symptoms the way the fuel circuit was laid out. If I slowly closed the choke to richen the mixture up, the engine would smooth out, but then start to die because of it being too rich.Thanks in advance for any guidance. Go figure, a 11.5 hp 4 stroke would have me scratching my head.

[Tom D.]

Well on the Quadrajet carbs had a similar problem with a welch plug. They would epoxy them in so they didn't leak.

[Tom Foley]

Just clean the area and put a small piece of good duct tape or hockey tape on it to try it . for sure it's dead lean .

[Quinten]

The way the casting is, there really is no way to tape over it. Screw it, the new carb is on its way. I'm ashamed to tell ya how the walk behind feels today. Been a long time. Guess I got a little spoiled.

[olboatman]

Quinten Welch plugs should be held in and sealed off by compression. I think the hole is overbored so they use epoxy to seal it. I would check your new carb and if there is epoxy around the plug I would clean it -- ad some flux and a drop or two of silver solder to seal it . It is simpler than it sounds. Of course this works if the carb is metal. Hope this helps. Gary