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Briggs & Stratton Garbage Carb

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  • Briggs & Stratton Garbage Carb

    A friend brought me his Craftsman lawn mower that has a Briggs motor on it. He couldn't get it to run. If you keep pumping the primer bulb you can keep it running.
    That told me all I needed to know. I took the carb apart soaked it and blew out all the passages etc. etc. put it back together and it still wouldn't run. I could keep it running if I kept spraying ether down it's throat but that was it.
    The carbs on these are the worst design I've ever seen. There are no adjustments at all. The internals are drilled to a specific size for proper fuel at a given (set) RPM.
    Apparently it was clogged somewhere internally. I put a new one on it and it started right up.
    Using ethanol gas doesn't help either. The small passages corrode and can't be cleaned with solvent or compressed air.
    Over the years I've repaired and cleaned probably hundreds of small engine carbs that were gunked up. This is the first one that had to be replaced.
    If it had a low and high speed idle jet like they all used to I'm sure I could have cleaned it out.

    JL...........


  • #2
    Beats their old Vacu-jets

    things where directly attached to the fuel tank and picked up the fuel to feed the venturi directly from the bottom of the tank,

    full tank - engine ran rich, near empty tank - engine ran lean... (DUH) but hey no float assembly needed and the engine ran perfect with a half tank full of fuel lol

    Comment


    • #3
      Agreed!
      We can thank ethanol and the EPA for the lack of adjustability of these low dollar carbs. They have now been regulated to the point of being as disposable as a Bic lighter.
      Thankfully cheap replacements are available from where they probably came from in the first place. I usually stock about a half dozen of the more popular ones. It's not if I'll need one but when.
      Home, down in the valley behind the Red Angus
      Bad Decisions Make Good Stories​

      Location: British Columbia

      Comment


      • #4
        I fixed up a B&S engine not too long ago that was the same way. Replacing the preloaded vacuum diaphragm that drew fuel into the carb did the job. Small gasket with a couple "tabs" in it over the fuel inlet in the carb. It was was hardened and deformed. But judging on your statement:

        Over the years I've repaired and cleaned probably hundreds of small engine carbs that were gunked up
        I'm not telling you anything you don't already know, if it even applies to that carb.
        My recommendation?

        No matter what I tell you, get a second opinion.

        Comment


        • #5
          Originally posted by A.K. Boomer View Post
          Beats their old Vacu-jets

          things where directly attached to the fuel tank and picked up the fuel to feed the venturi directly from the bottom of the tank,

          full tank - engine ran rich, near empty tank - engine ran lean... (DUH) but hey no float assembly needed and the engine ran perfect with a half tank full of fuel lol
          They pulled fuel up into a well or reservoir from the long tube, then a short tube would feed the engine from a consistent fuel level, not straight from the bottom into the carb itself. Never had much problems with them other than the odd ruptured diaphragm.
          Home, down in the valley behind the Red Angus
          Bad Decisions Make Good Stories​

          Location: British Columbia

          Comment


          • #6
            Willy - cheap replacements is an understatement


            two weeks ago i go to use the weedeater and the prim bulb along with one of the hoses shoots craps,,, so i go on line to see if i can find a replacement bulb and some hose, no such luck but find an ENTIRE carb with bulb and hose, two extra prime bulbs, two in tank weighted fuel filters - a spark plug, all for 12 bucks free ship...

            get it in - 15 minutes later the thing fires up and does not even need a screw turned for adjustment lol

            how can you beat that???

            Comment


            • #7
              Originally posted by Willy View Post
              They pulled fuel up into a well or reservoir from the long tube, then a short tube would feed the engine from a consistent fuel level, not straight from the bottom into the carb itself. Never had much problems with them other than the odd ruptured diaphragm.
              Im not familiar with that type - these were direct feed to the venturi, the tank was fairly flat and wide which would reduce the negative affects - they did run different from full to empty,,, im sure of it...

              Comment


              • #8
                Originally posted by A.K. Boomer View Post
                Im not familiar with that type - these were direct feed to the venturi, the tank was fairly flat and wide which would reduce the negative affects - they did run different from full to empty,,, im sure of it...
                I have what Willy describes, and find that a new diaphragm every couple of years is mandatory.

                Comment


                • #9
                  The ones that im talking about did not have any kind of diaphragm just a gasket to seal between the tank and the carbs body,,, now were going back something like 50 or so years,

                  there was all kinds of versions of Vacu-Jets and Pulsa-Jets too, I always thought the pulsa's were the ones with the diaphragm and operated like a two stroke carb as it used the crankcase pulsations to pump fuel...

                  the vacu-jets im talking about were about the most simplest carb ever invented,,, there was only one moving part - the throttle plate... count two with choke and yes it did have some adjustment screws...

                  Comment


                  • #10
                    You're right AK, I was thinking of the pulsa-jet.

                    Non-ethanal gas is your friend if you can find it. Since switching everything over my carb issues have ceased.
                    Last edited by Willy; 09-02-2018, 11:34 AM.
                    Home, down in the valley behind the Red Angus
                    Bad Decisions Make Good Stories​

                    Location: British Columbia

                    Comment


                    • #11
                      Originally posted by Willy View Post
                      You're right AK, I was thinking of the pulsa-jet.

                      .
                      im pretty sure it had one of those slide pull out chokes - and you push it in it opens a top port, and pull it out to choke it.

                      I had one on my mini-bike - not going to mention any names (well full ones anyways) but got it to where it would kinda idle and get me around so had a big plan i was going to give this total little hottie a ride on my mini-bike, planned it for weeks, had a crush on her bad and she kinda had a half crush on me, so head through the subdivision and get to her house - no calls, never even mentioned it to her and here i am idling the thing at the end of their driveway all kinds of racket and smoke and trying to hold the engine back cuz the centrifugal clutch was half engaged - only way i could get the pos to idle,,, old white hand-me-down helmet from an older bro who should have thrown the damn thing away - mostly white - some gray primer some bondo coloring and of course bare broken fiberglass showing through,,, plus thing had an incredible odor and not a good one...

                      all the sudden her front door opens and it's her dad --- oh crap and her moms right behind him - their staring at me, Tammy's in the window looking out like WTF??? i gave the throttle a twist and then gallantly tamed the beast by holding it back - did it about three times, then look back at the window - same expression like WTF???

                      then see her dad shaking his head "NO" I started then realizing just how much of an idiot i must have looked like, my mini-bike was a piece of crap - no helmet for her ? good move on her dads part that's for sure - i felt like a fool - thank god the vacu-jet did not let me down at that moment, at least i got to goose it and show her what she was missing - all 3 1/2 ponies including some really bad oil rings... lol id say "those were the days" but nope - they weren't lol things got a little better after that... lol

                      Comment


                      • #12
                        Originally posted by A.K. Boomer View Post
                        Beats their old Vacu-jets

                        things where directly attached to the fuel tank and picked up the fuel to feed the venturi directly from the bottom of the tank,

                        full tank - engine ran rich, near empty tank - engine ran lean... (DUH) but hey no float assembly needed and the engine ran perfect with a half tank full of fuel lol
                        I don't remember what a vacu jet carb was. As far back as I can remember the old Briggs with the straight carb, pull out choke at the end and the tank screwed to the bottom of the carb.
                        It had a long plastic pickup that went almost to the bottom of the tank. All I can remember is a gasket being between the two.
                        Usually pulse diaphragms were used on two strokes.
                        I also remember the Briggs with the wet bath oil air filters sitting on top of the carb. and then the real old ones that were all cast iron blocks.

                        The wet bath air filters were a PIA...... every time you tipped the mower a little the oil would run down into the carb, smoke like hell or foul the plug.

                        JL..............

                        Comment


                        • #13
                          I quite like that type as being totally self contained with fuel tank you can just swap a spare on. The ones I hate are where they have a separate carb but special moulded plastic fuel tank that is part of the go faster streamlining and inevitably decides to leak.

                          Comment


                          • #14
                            Originally posted by Willy View Post
                            Agreed!
                            We can thank ethanol and the EPA for the lack of adjustability of these low dollar carbs. They have now been regulated to the point of being as disposable as a Bic lighter.
                            Thankfully cheap replacements are available from where they probably came from in the first place. I usually stock about a half dozen of the more popular ones. It's not if I'll need one but when.
                            You right......... All I had was the model number of the mower, no engine numbers so I had no idea what the part number was for the carb. Can't take a wild guess because there are a million variations to chose from.
                            I gave my friend the model number and he calls Sears Parts Direct.......... They give him the PN# from the mower model number, not knowing he buys the carb from them at $75 smackers plus shipping. I thought that was outrageous for that carb. After getting the PN# I looked at ebay........ $8.50 shipped. I told him to send it back to Sears.
                            It's no wonder why Sears is going belly up. Maybe they are trying to save themselves from CH 11.

                            JL.................

                            Comment


                            • #15
                              The pulsa-jet and vacu-jet carbs were somewhat similar in appearance.
                              On the pulsa-jet carb the diaphragm was located on the side and could be accessed thru a small cover plate.
                              On the vacu-jet the diaphragm was larger and was sandwiched between the carb and the tank.





                              Lots of good info below regarding servicing these and other makes and models of outdoor power equipment carbs.

                              http://outdoorpowerinfo.com/repairs/
                              Last edited by Willy; 09-01-2018, 05:27 PM. Reason: grammer
                              Home, down in the valley behind the Red Angus
                              Bad Decisions Make Good Stories​

                              Location: British Columbia

                              Comment

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