Return to the Tractors Forum | Post a Follow-Up

 o
small Briggs & Stratton lawn mower runs unstable

Posted by eddeheer none (My Page) on
Tue, May 13, 14 at 14:52

Hi there,

I've run small a B&S lawn mover for two years without any problems. All of a sudden (but after cleaning the machine etc) it began running unstable/irregular. Strange enough when de machine allmost runs out of gaz is starts working great. Filling the tank the same problem appear

I hope this forum wil help me out.

Thanks and regards,
Ed


Follow-Up Postings:

 o
RE: small Briggs & Stratton lawn mower runs unstable

Have you changed the air filter?
Mike


 o
RE: small Briggs & Stratton lawn mower runs unstable

Hi Mike,

I did clean the (foam) air filter because it was dirty and drained with oil. Without result. Even with de air filer out the machine runs unstable.

Thanks and regards,
Ed


 o
RE: small Briggs & Stratton lawn mower runs unstable

Try running it w/o the air filter. If the problem persists then you have a rich mixture caused by the choke,if it has one, or the carb has a fuel mixture problem. How does it run at low idle?
Mike


 o
RE: small Briggs & Stratton lawn mower runs unstable

Hi Mike,

I'll try this weekend and keep you posted.

Thanks,
Ed


 o
RE: small Briggs & Stratton lawn mower runs unstable

If you can post the Briggs Model, Type and Code, that would help. Interesting that it runs well when almost out of gas.


 o
RE: small Briggs & Stratton lawn mower runs unstable

I tried running without the airfilter. No positive results. The machine still runs slow and unstable.

Its a B&S XC35 (classic)

Thanks in advance,
Ed


 o
RE: small Briggs & Stratton lawn mower runs unstable

***"Its a B&S XC35 (classic)"***
Well, that is just precious.
But that stuff is just marketing hype.
Look the engine over closely and you will find the "real deal" in identification numbers, most likely will be numbers pin prick etched onto a riveted metal ID plate.
The numbers will be called MODEL NUMBER, TYPE NUMBER, and CODE.
Those are the only numbers that mean anything to a mechanic or parts person.


 o
RE: small Briggs & Stratton lawn mower runs unstable

I think I found the numbers:

9D902 2096 B1 05102751

See attached photo.
Thanks and regards,
Ed


 o
RE: small Briggs & Stratton lawn mower runs unstable

Having looked at the Briggs parts manual (IPL) for this engine, I suspect that the carb mounting diaphragm/gasket (where the carb mounts to the fuel tank) may have a defect in it which is feeding extra fuel through the main jet by engine vacuum instead of simply pumping the fuel in pulses.
The fact that the engine seems to "run better" just before running the tank empty supports the notion that the carb is feeding extra fuel to the engine.
If a new carb mounting diaphragm does not solve the problem, replace the carburetor assembly.


 o
RE: small Briggs & Stratton lawn mower runs unstable

Hi,

Thanks for the quick response. I'll try to find the parts you mentioned here in the Netherlands.

P.S. do you have a link to the parts manual you refer to ?


 o
RE: small Briggs & Stratton lawn mower runs unstable

Try this. Then select Illustrated Parts List (IPL).
http://www.briggsandstratton.com/us/en/support/manuals/results?NTT=09D902-2096-B1


 o
RE: small Briggs & Stratton lawn mower runs unstable

Hi 'Mownie'

I found the diaphragm and gasket and replaced them this evening , together with the spark.
The machine runs great !

Thanks and regards,
Ed


 o
RE: small Briggs & Stratton lawn mower runs unstable

Glad to hear a good report.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Tractors Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here