Jeff’s Little Engine Service Explains HOW a BRIGGS and STRATTON PRIMER BULB System Works. Lawnmower PRIMING Button PROBLEM can be FIXED. PRIMER BUTTON will not work. Gaskets. 3-7 HORSEPOWER ALL BRIGGS AND STRATTON motor with a PRIMER BUTTON BULB.
Music by BonzaiRod. “George”
Copyright 2016 Jeff’s Little Engine Service
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PLEASE KEEP IN MIND when you are watching my videos: I am showing you the least expensive, quickest “backyard” methods for repairing or servicing your lawnmower. Replacing all components such as gaskets and fuel lines is always recommended when rebuilding or repairing equipment. With these videos I hope you are able to fix and repair your lawnmower yourself with minimal parts, knowledge and tools. Always work safe. Thank you for watching!



48 thoughts on “Briggs and Stratton LAWNMOWER PRIMER BULB PROBLEMS. Won't PRIME. WILL NOT Cold START. HOW TO FIX

  1. I have a Briggs 500E with the air purge primer. It will only run off gas fed into the carb for a few seconds. Primer has suction and gaskets are good. Gas is not going into the carburetor whatever I do

  2. Holy shit, I'm glad I found this video. Been troubleshooting my mower for days, and the double seal fixed it. Thanks a bunch!

  3. I did this to a mower that I'm working on, and the first two times I pushed the bulb, it "burped" a small drop of gas. After that, nothing. The engine was warm because I sprayed a little cocktail of gas and two-cycle oil in there to warm it up for an oil change. Would a warm engine NOT prime since it doesn't need to? I've been fighting this mower for a while now, and I'm not sure what else to try.

    FYI The carburetor has been completely disassembled and thoroughly cleaned in an ultra-sonic cleaner. All venturi have been cleaned with fine welder tip cleaners. I verified all passages were clean by shining a light through them. After all that, it still would not prime or start. I tried this tip, and I got two drops of gas to go through the carburetor.

  4. Omg Jeff, you saved my day. I didn’t even know that tightening too hard would warp that cover. Best video on YouTube by FAR

  5. I typed in “push mower won’t prime” on google and this was the the first thing I saw on google…. and it’s the exact same mower as mine smh lol

  6. This worked for my Craftsman mower with Briggs and Stratton Engine! Needed prime at least 10 times and took 10 pulls, after stacking one extra gasket, it now only needs 4 primes and 1 pull! Thank you!

  7. Thanks for this. Rebuilt a 2005 Toro SR4 and it kept having hard start problems. Looked and saw no gas coming up the emulsion tube with priming. Stacked the old gasket with the new and voila. Fixed it.

  8. Thank you so much for this tip. I have a B&S 300E series mower that I cleaned up but wouldn't start because the primer blub didn't seem to do anything. I was very frustrated and ready to give up and just buy a manual push mover for my little lawn.

    Then I saw this and loosened the two screws holding my carb plate and voila, the mower started.

    It would had never occured to me that this was a potential fix.

    An aside: why are the B&S manuals (and website) so useless for troubleshooting? The main recommendation they have for any problem is to "contact your local authorised dealer". Pure balderdash: like I'm going bring a $150 mower in for repairs. I hated the idea of throwing away my old unit and getting a replacement because of the waste involved. Thank you again for the help.

  9. One more thing to check for a lack of priming. Notice that there is an air hole in the bulb.  This allows dirt in and in my case clogged the screen underneath the bulb. Cleaned the screen with some gasoline and a brush and she was priming again.

  10. I wish I searched out this video before I cussed for 2 hours working on one of these. With the double gasket I fixed it in 10 seconds. Seems like a stupid design to have a giant channel that needs complete gasket coverage…

  11. I can’t believe this actually worked. I installed a new carburetor and it still wouldn’t start. Primer was not working. At your suggestion I put the old gasket over the new and it worked. This just amazes me. Thanks

  12. Put masking tape on the air filter groove with the sticky side on the groove, press it on good so the sticky side of the tape seals the groove, trim it with a razor blade or xacto knife. Put the gasket back on top and bolt it up. It will now squirt gas inside the carb because the tape sealed the groove and no air leaks out ….. problem solved !!!!

  13. Thank you for this video. I’ve found a small push mower with a Briggs & Stratton engine in a garbage dump. Everything just needed a good cleaning (new plug, new aur filter), and the gas tank had a leak from rust. Once I replaced the tank she’d be as good as new. So I thought. Since then, I’ve been pulling my hair out.

    Purchased a new gas tank/carb combo for small change, relaced the old one. No prime spray from the bulb. I removed the new carb from the gas tank and put the old one back on because I knew it had spray. Now the old one won’t work. So I’m sitting here over this insignificant piece of machinery thinking, “It can’t possibly be that hard? WTH?” I’ve coined an expression over the years from experience that “when you think a project will take you about 5 minutes, it will end up taking about 5 hours”; case in point.

    But, I think you may have solved my problem!

  14. Nice…. YouTube saves the day again. Mine had no visual smash marks like the one in the clip did. 2 gaskets and she is a religious squirter again! Before she did not want to squirt no matter how I used my finger or how fast I did it. I taught maybe it was my finger position at first. But now she squirts like old faiful on the first pump and fires right up! It's nice when tips are shared and easy to find on you tube. I need to contribute tips and tricks on here.

  15. Very useful, thanks! My mower primes, but only runs for a few seconds unless I hold the primer bubble in half way–not a little, not all the way, half way. If I hold it in half way, the mower runs fine! What gives? Been years since I tried to use this mower. All I did was put in fresh gas, check the spark and filter–as I said, it runs fine if I hold the bulb half way in!

  16. This does really work,I over tightened,so it wasn't sealing good,although I put alittle vaseline behind gasket,it works well now,good info.

  17. I tried two gaskets and it still won’t prime or suck any fuel through brass valve.Even if I prime using starter fluid,gas won’t flow through brass valve.
    I put new jet in it,sprayed out holes,but I can hear air bleeding or leaking when I pump bulb.

  18. If anyone reads this, I don't have a briggs and straton lawn mower, I have a yard machine mower that starts but the prime won't stick. Any suggestions??? I've flushed the fuel tank, and used MIB, then placed new fresh gasoline in it. It wants to start but it won't stay started. Someone said check the spark plugs, done that. Any help would be greatly appreciated.

  19. I own a lawnmower with that same style engine and the primer will not prime so I put 2 gaskets behind that plastic part. The engine runs a little erratic and it is usually hard to restart it. Do you think the plastic part is warped?

  20. Replaced the gasket and even doubled up. Still not getting fuel in the carb. Continue to here the bulb suck for air. Suggestion?

  21. I have a Briggs engine that isn't starting I've checked the spark, cleaned out the carburetor twice, I've switched a carburetor that I know works onto it, I've checked to make sure the throttle had enough tension and check the air filter, nothing has worked. I had no idea that the back of the air filter housing could get warped and cause it to not start though. Thanks for the tip!

  22. What if no gas is coming up through the brass port, even though I replaced the primer bulb with a new OEM Briggs bulb? I'm wondering if the port is clogged; if so, how do I clean it? Do you have a video on that? I have a Briggs 6.5. Thanks, Jeff!

  23. Good tip, I've done it before. I found it you put a little gas on the gasket , sometimes one will do the trick. Strangely enough.

  24. Wondered why there was 2 gaskets on the backing plate of my lawnmower when I went to clean the carb, now I know why. Thanks for explaining the reason why. Happy Christmas.

  25. I had this same problem on one of my mowers and used the 2 gaskets to fix it like you did. It worked a lot better buy not quite as good as a new plastic backing plate. Great video!!!

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