Briggs and Stratton Primer Bulb Replacement 3.5HP

In this tutorial we will be demonstrating how to replace a primer bulb on a Briggs & Stratton diaphragm carburetor.


    • Flat Head Screw Driver
    • Replacement Primer Bulb
    • Air Compressor/Method for Cleaning

Step 1

Gently pry out the clips shown in the video. Push the retaining plastic clip up, this will release the primer bulb.

Step 2

Clean underneath and clear any blockages that would cause the primer to fail.

Step 3

Install the new primer by clipping it in place, or replace old if you’re just cleaning.

14 Responses to “Briggs and Stratton Primer Bulb Replacement 3.5HP”

  1. Thanks for posting the tutorial about replacing the primer bulb on a Briggs and Stratton 3.5HP lawn mower. It was just what I needed to help another help me in replacing one that was pierced.

  2. Thanks good instructions I appreciate you. Don Williams retired/retarded truck driver

  3. Replaced primer bulb but it is not pulling the gas into carburetor, What’s the problem?

  4. It’s a 3.5hp briggs and Stratton classic. Do you have a the kit for this carburetor?

  5. I broke the retaining clip –I think the guy in the video did too –there’s an edit right where I broke mine!


  6. Excellent ! Was stumped on replacement

  7. Runs a short time after I prime the engine,just seems to run on the primer gas,what’s wrong?

    • This means that there is a blockage/problem with your carburetor, It is likely is needs to be cleaned and possibly have the diaphragm replaced

  8. My lawn mower won’t start after priming. Removed the spark plug, poured some gas on it and it will start. It runs beautifully but after shutting it off, it won’t start again. Any suggestions

    • That would suggest there is a blockage/problem with your carburetor which is stopping the fuel reaching the spark plug. It will need to be cleaned and probably the diaphragm replaced.

  9. Tore my carb down and cleaned and have a new bulb. There is a small steel ball and a seal/cup that fell out and have no clue where it goes. The ball is very small and the cup has a small hole in the center. Thanks for the help.

    • Hi Mike

      The ball & cup sit directly behind the primer bulb, There should be 3 holes behind the primer bulb, The cloest one to the air filter should have the cup & ball inserted.

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