Briggs & Stratton 6.5HP lawn mower carburetor clean & rebuild – carb welch plug removal replacement

My Scott lawn mower will not stay running for more than 5 sec. I have newer spark plugs, air filter, oil changed, and new gas?! What next? Clean and rebuild the carburetor. It works great now. Model Series 1216xx Type 0015 through 0668
Mr Gasket Sheet @ Amazon:
Here are the procedures:
1. Remove carb bowel nut, float pin, float, needle, seat and welch plug.
2. Clear jets, valves and all passages with wire
3. Clean jets, valves and all passages with carb cleaner and clear all with compressed air
4. Replace float pin, needle, seat, welch plug and gaskets

B&S Website:



26 thoughts on “Briggs & Stratton 6.5HP lawn mower carburetor clean & rebuild – carb welch plug removal replacement

  1. Very helpful video.
    I was having difficulty understanding Briggs and Stratton's explanation of how to place the needle seat and your video made it very clear.
    Thank you. 

  2. Very helpful information, a question regarding a 2 stroke Tecumseh Lawnmower carburettor, if the passages under the welch plug are blocked, will this cause the carby to flood, as I have installed a new needle and seat, float has no holes, is set to the manual specs, but carby floods. I have not removed the welch plug because these parts are hard to come by in Australia for these engines. Any ideas appreciated! Cheers.

  3. is this clear thing that you using to clean the bowl gasoline? i mean is it normal for gasoline to be clear on where you lieve?

  4. Old bad gas causes problems. When storing gas or a vehicle it is important to use it up yearly if you added Stabil or Seafoam to it when you filled up. It is easier to run the vehicle out of fuel and put fresh in yearly than deal with the problems that bad fuel causes.  Most small engine problems are due to gas going bad and not because of ethanol. Small engines have ALWAYS had problems with stale fuel gumming up the carburetor when left in for long periods of time.
    When a small engine like a lawn mower, leaf blower, chain saw, is being put up for the winter run it out of fuel before putting it away.  In the spring when filling your gas can for the first time add some Sta-Bil or Seafoam to the gas to extend its life. Gas generally starts to go bad after 30 -60 days. By adding the fuel stabilizer it will extend its life. 

  5. I don't understand what the Mr Gasket part was about – doesn't the carb kit come with the replacement? Why the need for Mr Gasket sheet?

  6. in center of carb where bowl screw goes there are two holes ,assuming jet?,should i be able to stick wire all the way through both holes?

  7. I did not see a bowl nut washer installed on the bowl nut. Extremely important. It keeps the float bowl from leaking!

  8. i have this same kit, thanks for the details, would not have thought about the drill, or wouldnt even have fooled with it, if i hadnt seen it for myself…great job…i still havnt found a use for the foam washers

  9. Good vid–thanks! You don't have to drill out those inner welch plugs. I just used a dental pick through the little holes/ recesses next to them and popped them out. Quicker and easier, and you can reuse them if necessary.

  10. My Troy-Built 320 has this exact carburetor. It's 4 years old. It would start but then die after 5 minutes and not start until it was cold again. The choke mechanism was working fine and I had ignition spark. I figured the problem was carburetor related so I took it apart as in this video. I cleaned everything with carburetor cleaner, poked wires thru the jet and various ports and blew it out with compressed air. I didn't use a rebuild kit. I also cleaned the fuel tank and fuel line. I put it back together and it runs perfectly. I think dirt or particles in the gas cause the problem. I installed a "Briggs & Stratton In Line Fuel Filter Part # 791891" so I won't have anymore dirty fuel problems.

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