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B&S Push mower troubles

Posted by tnshooter83 (My Page) on
Wed, Apr 14, 10 at 1:02

I mow my Grandmothers lawn, and she has a B&S 4hp push mower.
I don't currently have a model or any number.

I can get the mower to run, but it involves a few odd steps.

1. To get it started you have to prime the carb by pressing in on the bulb.
I normally press it in 6-10 times.

2. Pull the starter rope until it act like it "might" run. Then prime it for 6 more pumps of the bulb.

Next is the tricky part, you have to pull the starter rope until the mower run.
Then very quickly you have to keep pressing the prime bulb to keep it running. (all while holding down the throttle handle)
After about a minute, it will then all of a sudden start wanting to die if when you press the bulb.

Then, and only then will it stay running. It will run "ok" but not with the power it "should" have as if it were working properly. Then all of a sudden it will die, and you have to repeat the starting process all over again.

Any ideas? I'm figuring it is a carb problem. Are the carb on these things hard to rebuild?

Follow-Up Postings:

RE: B&S Push mower troubles

  • Posted by baymee LehighValleyPA (My Page) on
    Wed, Apr 14, 10 at 11:13

I believe you have a carb mounted on top of the gas tank with 5 screws. Buy yourself a tank diaphragm kit, about $6, and replace the diaphragm.

Remove the tank bolts and the governor lever from the carb, remove the screws, lift up the carb, replace the gasket and rubber diaphragm, re-install the carb. If the primer bulb doesn't have holes in it, keep it, or replace it. Everything should be self-explanatory and easy to do.

It should not be necessary to push the primer bulb more than 3-5 times. With a new diaphragm, maybe twice is enough.

RE: B&S Push mower troubles

Also check your air filter. That may be keeping the carb. from working properly.

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