How to Clean / Rebuild Briggs and Stratton One Piece Flo-Jet Carburetor

this carb is off my 12 horse briggs and stratton flathead single cylinder engine. Hope this helps you with cleaning/rebuilding briggs carburetors, i will also make one about the 2 piece carburetor too, at some point. thanks for watching and as always, feel free to comment / message me with questions and comments. thanks again.



40 thoughts on “How to Clean / Rebuild Briggs and Stratton One Piece Flo-Jet Carburetor

  1. that switch i believe is the on/off switch i thought it was the choke as well. because with that swtich off there is no power when turning the key. i just had to drain the old gas out, that didnt even look like gas any more, and now she purrs like a kitten!

  2. Need to get an air compressor and make sure you blow all that loose junk out from the passages inside the carb body.

  3. Wanted to thank you for the great vid on this carb. You explain things really well and made the job very easy for me. I also really appreciate allllll the little helpful things you mention along the way,….the kind of things you can normally only learn thru years of experience, which you obviously have. Thank you for sharing!!!! You're an excellent teacher!

  4. Quick question, on the newer two piece style carbs, does the bolt on the bottom of the bowl have any orifices? The reason I ask is that I just got a 12.5 briggs and the bolt has no holes at all.

  5. You mention a little rubber o ring on the needle valve, I am rebuilding a one piece with no instruction sheet. Where is this o ring used and on what carb?

  6. Hi fnaguitarplayer9 just wanted to jump on and say a huge thank you mate. Copied everything step by step. She started on first kick. Now I just have to adjust idle and all good cheers, Ben

  7. Just wanted to say thanks.  I did as you suggested and it started on the first try and runs smooth.  Guys like you make the the internet a great tool.  Much appreciated.

  8. Hi  fnaguitarplayer9. I have enjoyed your videos but I have an engine problem I cannot seem to resolve.  I have a B&S 281707-0200-01 engine on my Craftsman 917.254660 garden tractor that has developed an engine problem. Last season the engine would start normally and started to cut the grass and the engine ran for about 10 minutes and then suddenly quit and would not restart. I found to get the tractor back to the garage I had to remove the air filter and then the engine started and ran normally. This occurred several times so I thought the air filter may be clogged. I replaced both the paper/metal filter element and the green foam cover but the problem only became worse. By the end of 2014 season I could only start the tractor by removing the new air filter. I contacted you and B&S support and the final response was I needed to rebuild my carburetor.  Since the tractor is 25 years old I decided to order a new OEM B&S 491031 carburetor and I have now installed it. I have set the speeds and I still have the problem. While setting the idle speed screws with no air filter installed I was able to set the high speed idle and I started the engine at least five times. Next I completely installed the air filter unit and now I could not start the engine. I next removed the top cover and the air filter. Now the engine started and ran normally and my tach read was 5440 RPM at high throttle. So with the engine running I installed the air cleaner and the top cover and the engine continued to run normally, still about 5400 RPM, but if I shut down the engine and 10 seconds later went to restart the engine it would barely fire at all and would not start. I then removed the air filter and when I started the engine, the open carburetor blew a little atomized fuel and after a second started then started and ran fine, 5440 RPM. I am looking for any help. To me it looks like when starting the engine with the air filter installed it seems the engine is flooded and when the filter is removed the air fuel mixture is good and the engine starts.  Any help or ideas would be appreciated.

  9. My 10 hp B&S is getting a rebuild thanks to the small screw in the throttle butterfly coming out and bending the exhaust valve. To get to the throttle butterfly to replace the screw requires removing the welch plug, choke butterfly and emulsion nozzle. The emulsion nozzle is not wanting to come out. Any ideas on how to free it up? Yours came right out.

  10. fnaguitarplayer9 Today before I started the tractor I cleaned and gapped the spark plug. It had gotten some carbon fouling it. Now the engine started right up and after high and low idle screws was running smoothly at both full throttle and low idle and repeatedly started with both the air cleaner and cover installed. Now the tach would read 2960 to 3000 RPMs at full throttle and 1350 at low idle. This is with the tach set to count on ever revolution. Both the full throttle and low idle speeds seemed a bit low but not real sure of the accuracy of this inductive pick up tach. On the B&S engine section of the tractor’s manual there is Throttle Control Cable Adjustment procedure. It outlines a cable adjustment that is supposed to align holes on the “governor control plate” and the “slide plate” with full throttle. Their illustration is not very clear but from what I can see these holes are off by less than 3/8” on my engine. I have not adjusted this at this point or changed the factory setting of the Idle Stop screw. Wonder if it is critical to precisely adjust the Throttle cable to get the engine speed closer to the 3600 RPM full throttle and 1800 RPM at low idle? With the adjustments of the high and low idle the engines seems to run much smoothly than it has in a long while. Any advice as to how much more precisely I should adjust the Throttle Cable and the Idle Stop screw would be very much appreciated. Thank you so much for all your help.

  11. fnaguitarplayer9 Well yesterday was a bad day. Looks like I managed to somehow seize my engine. I was able to start the engine with no problem and was running good. Ran it for maybe five minutes then drove it around. At this point it made a shrill noise and then just quit like you shut it down with the ignition key. When I went to restart it the starter engaged but would not turn the flywheel. I even hooked up a 12 VDC charger in parallel with the battery and put it in a start mode but the starter still would not turn the flywheel. I had checked the oil before I ever started it and the level was good. I even drained the oil at this point and there was a normal amount of oil in the crankcase. I filled it again with Castrol 30W HD oil but still no luck. Anyway if I cannot figure anyway to unseize the engine it looks like a new tractor is in the cards. Anyway thank you so much for your help. Ron

  12. One important thing on flo jet, make sure that flange surface between head and carb is flat. After 30 years might cause problems. John Deere 111 runs like a dream.

  13. fnaguitarplayer9, i rebuilt my 1 pc flowjet on my briggs & stratton 170707, replaced the float "plunger/needle", the throttle shaft, the choke shaft, the choke plate, new float bowl gasket. cleaned the whole thing, removed the venturi for the throttle valve replacement, cleaned and replaced the venturi, cleaned all brass components good. adjusted the governor per your video, fresh gas, fresh fuel line, fresh fuel filter. when using the starter, and choke on, the carb pops, spits gas out the air inlet, backfires, spits flames out sometimes, sometimes white smoke out the muffler, fuel is pooling in the carb bottom. the engine ran on starting fluid before i removed the carb, i didn't want to waste time on the carb if it didn't. with the choke off it still spits out raw fuel from the air inlet. what is wrong?

  14. Thank you for the video, it was very helpful. I live in Memphis and I am trying to find a carburetor for a Murray Rider. Does anyone know where I can locate one….

  15. Hi, I was given a 12hp Murry. I checked the oil, put in a battery, some gas in the tank. I turn the fuel inline cut off valve on and started cranking the engine. I sprayed starting fluid down the throat to give it a boost starting. The engine started, sputtered a bit then started running a little smoother. Then I noticed gasoline was really pouring down the carb and it began surging. I didn't notice much about the carb as it was getting dark. I think it may have a carb like the one in your video. Does these carbs have rubber seat in them and do you know a rebuild kit part number? Thanks. I enjoy watching your videos very much.

  16. I'm getting gas in my crankcase.  is it the float?  I have the same carb as in the video.I took the carb off and apart and cleaned it for days in a chemical bath.  Needles and jets and screws even float look new now.  I rebuilt the engine. Put it back together and on start up it filled the crankcase up with gas.

  17. Just watched this video , and the one adjusting the carburetor video. Great by the way. I rebuilt and adjusted the carb on my 11 hp Briggs as according to your videos. It runs like a champ on flat ground, but as soon as you hit thick grass or go up an incline it bogs down and dies. what could be the issue with dying under load?

  18. Is there a replacement carb like this from stens or something? I'm working on one now for my uncle. I took the bowl off and it's pretty corroded. I cleaned it the best I could and sprayed carb cleaner into it but still on the mower. It went from not starting at all to running but had some small pops every now and then. Maybe if I completely disassemble it I'll have better luck

  19. can yo link a rebuild kit for this carb and the float bowl jet screw that holds the float bowl on and a float and a jet please thanks in advance

  20. Working on a 12HP I/C Briggs probably 30 years old, with a carb that looks like the one in your video. Fuel doesn't seem to flow into the carb bowl, so I'm assuming it is the little needle valve which is attached to the float? (or the float itself) Engine starts and runs on starting fluid, and I've sprayed the heck out of everything else with carb cleaner. Any advice would be appreciated.

  21. I have an older briggs and stratton 11hp (400cc) motor with the same carb. Does this setup need a fuel pump? Or does the carb pull suction from the fuel line utilizing the float?
    Steve D.

  22. Hi, I need the ELBOW on your 2 Piece Carb. I want to Restore my John Deere 111, but it has the FLOW JET 1 Piece which is Expensive to buy :((((. If I have the Elbow, or find one that is CHEAP. I can use the AFTER MARKET CARB for a lot CHEAPER :))). they want $180.00 for the FLOW JET, while I can get an ELBOW and another CARB for maybe $50.00 Total? So if ANYONE here knows the Part Number for the ELBOW? Please post it here? THANK YOU :))))))))))))))))))

  23. I just bought an 87 Briggs flathead for 20 bucks .it has the one piece flow jet carb on it and all I'm missing to get it running is the freaking bowl!!! >:((((

  24. Hello.I have an briggs and stratton 400 cc 11hp It leaks gas on the inside of the carb adn out the bottom to the ground. IM going to do the same thing you did hopefully that will do the trick Thank you for the video and got me out of a jam

  25. Good afternoon sir .Thank you very much for the help on that leaky carb from the briggs 400cc motor. Took everything apart and cleaned everything like you did .Fixed the problem .The tractor is a 1988 sears wheel horse LT1100 11hp .It was my dads .The next thing i need to move and re wire the mower deck handel for the blades .The saftey switch is old and shot .Makes it a real pain to start. I would like to put a toggle on the dash. Again thanks for the help.

  26. Hi,

    after a diesel mishap, I rebuilt my 8hp carb with help of your video and the original carb rebuild kit. I doesn't really want to start anymore. Sometimes, It will run for a couple of strokes, then dies down. Best was when it ran for like half a minute completely fine and then died on me. Feels like its not getting enough gas or there is air stuck in fuel line cutting of the supply to the engine. Would you have some suggestions for me?

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