Small Briggs and Stratton motors

There's a number of folks, some on this forum, that say that B&S make good motors. I don't doubt it, but ...
In my garage for maybe 15 years is an MTD 21" push mower with a B&S 4hp ("Quatro", I think) motor. I can flawlessly clean the carb/filter, put a new plug in it, etc etc, and, when started, it will run OK for about 5 seconds, then rev up to around max rpm's, then come down to idle speed and repeat the up/down rpm thing forever. It starts on the first pull, but there's something seriously wrong with design and/or manufacture. 25-35% of similar mowers around here do the same up/down thing.
So, my question is, how does one identify good B&S motors, and pass on the turkeys? I need a new, light-weight push mower and would like to be able to consider the ones with B&S engines without getting stung on a flaky motor. Do they make a good small mower motor that has a really good record and that is still available and identifiable (hopefully from the ads in the paper, etc)?
TIA, Willie
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wrote:

Has your current motor always surged like you describe???
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On Sat, 2 Jul 2011 20:22:25 -0700 (PDT), "hr(bob) snipped-for-privacy@att.net"
wrote:

Not always, but (for me -and- numerous neighbors) for many, many years. At least 6-8 years.
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wrote:

Too cheap?
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On Sat, 2 Jul 2011 20:22:25 -0700 (PDT), "hr(bob) snipped-for-privacy@att.net"

Sure asounds like a governor linkage or adjustment problem. Take it to a B&S dealer and have it looked after and it won't give you any more trouble.
By the way - I FINALLY killed and replaced my 1978 horizontal shaft B&S 4HP engine on my old 25" rotary mower. Bought a chinese Honda clone "kit" engine. All chinese equipment needs to be considered a "kit" because you can count on needing to dissassemble and reassemble at least some part of it before it will function as designed. Mine came with no connection between the carburetor and the fuel tank - - - - - .
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On 7/3/2011 8:37 AM, Stormin Mormon wrote:

Or, sometimes there is crud caked around the governor/linkages. A quick cleaning will sometimes fix the problem.
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Still waiting for the OP to tell us if this is a new or continuing problem!!!!
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On Sun, 3 Jul 2011 07:23:18 -0700 (PDT), "hr(bob) snipped-for-privacy@att.net"

From what I remember he DID say the mower has been sitting in the shed for 15 years - - - - -
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On Sat, 02 Jul 2011 22:04:28 -0500, Willie The Wimp wrote:

Governor problems perhaps. Fix it.
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Sounds like it's running lean. Try pressing the primer bulb a few times while it's running and see if it steadies out....
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