Briggs and Stratton Plastic Carb 300E series on a Murray, starts/ dies, carb clean. PART 1

Briggs and Stratton 4.5 , 300E series Plastic Carb on a Murray lawnmower, starts but dies, carb clean and fix how to. PART 1



24 thoughts on “Briggs and Stratton Plastic Carb 300E series on a Murray, starts/ dies, carb clean. PART 1

  1. got mine running as well! Still I would like to know the cause of the gas running out of the breather hole in the primer bulb. The only thing that I can think of is that I had the starter safety handle tied down when I was working on it yesterday but I tried that today and it didn't so I'm a bit mystified as to what I did to stop it.   Could blowing out the jets stop that from happening?    P.S. when you pulled out the jets you didn't show that the plastic throat would fall out! lol  I finally figured out how to get it back in by removing the jets and dropping the throat back in with the hole aligned so the jet held it in place.  Thanks for help on this and hope you keep making more excellent vids!!

  2. This is, by far, the best demonstration of the complete disassembly and cleaning of one of these new plastic carbs from Briggs. I have been looking and, so far, this is the best I have seen. I have a 550 EX that has a hesitation after in warms up like a miss. I think these things run a bit to lean but they can't be adjusted. I think I will take it apart and make sure it's all clear and see if that helps. It's been that way since it was new. Thanks, nice video!

  3. I have an issue with mine hunting or surging. I tried cleaning the carb, but that didn't solve my problem. Then, I went to my local Briggs supplier and purchased a kit and installed it. No luck this time either. I tried adjusting the governor spring after that, and that just caused it to surge faster. I need some help, sir. What the heck is going on here?

  4. Just want to thank you a lot. This video got my lawnmower working just right. It was the same model. Took it apart, nothing but gas in it. Cleaned it like you said and it started right up. Saved me some money. Very detailed from start to finish.

  5. thank you for the video, couldn't get my mower running, tried cleaning the carb but no luck. watched your video and my problem was with the little plastic jet assembly, cleaned that as you instructed and mower started on the very first pull.

  6. you probably get this alot…youre fucking awesome…my dad has the exact same mower….followed your steps….and worked like a charm….thanks alot

  7. Thanks for showing this! I had a brand new mower go bad after one month. I checked the spark plug, oil level, clean fuel, etc. But the damned thing would not start. Finally today I figured it pretty much had to be a clog somewhere in the carburetor, and sure enough those plastic fuel jets were clogged. Cleaned them out, and the sucker started on the first pull and sounded smooth!

  8. Aaron, would you happen to know the part number for the welch plug on this type carburetor. Mine fell out. Can I press it back on?

  9. you should mention when reinstalling the jet emulsion tube assembly that the center tube goes into a white hole in the bottom. I didn't pay much attention what it was for but it freely rotates in the carb housing. I used the red spray tube from a plastic safe carb cleaner to realign the hole so the jet assembly could go back in place

  10. Thank you so much, just finished doing the carb clean on my 140cc 5.00 B&S silver, works now thanks to you! really appreciate it.

  11. mines not priming i guess ill take it apart and clean out the jets.. you think this could be the issue?

  12. Same problem, same series engine, but on a Troy-Bilt I got at Lowe's. Engine had maybe 6 hours on it.
    I was worried that I would break something if I tried to remove the jet assembly but this video was quite helpful. I used a guitar string to clean the holes. It runs lean though–does anyone know the jet sizes?

  13. WTH… I had a briggs mower ran great for 30 years – never a problem. Last summer the motor finally wore out and got a new Briggs 300e. Ran OK then – except for the surging which is normal on these auto throttle models – but this year cant get it to start after winter. Lucky my warranty is still good.

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