Craftsman 7hp Briggs & Stratton


Old 08-14-12, 08:23 PM
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Join Date: Aug 2012
Posts: 4
Question Craftsman 7hp Briggs & Stratton


I am looking for some help in diagnosing issues with my Craftsman 7.0 hp Briggs and Stratton self propelled lawnmower.

Craftsman 917.378941
B&S 128602-0304-E1-031015-FB

The mower started acting up a few weeks ago by being difficult to start, and did not sound like it was running on full power. As soon as I encountered some taller grass than normal, it would stall out. This mower is a 7.0 hp and before had never had problems mowing through some tall thick vegetation! Once this drought set in and the grass wasn't as thick, the mower was still hard to start, but once running, it would die after 10 minutes or so.

Repairs made:
  • Replaced cracked primer bulb
  • New Spark Plug
  • New Air Filter
  • Replaced Magnetron
  • Oil Change
  • Carb cleaned and rebuilt with B&S rebuilt kit

Still will not start. After priming the bulb, after a few pulls, the mower tries to turn over, sputtering a bit and giving off some white smoke but never succeeds in actually starting. After a few pulls getting some sputtering, it no longer sounds like it is trying to start. Prime it again, and again the same result.

I am a fairly handy person, but this mower is driving me mad. I am on the verge of sending it in for someone to try to repair it...which irritates me to no end! Any ideas on what to look for? Thanks in advance!
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Old 08-14-12, 11:19 PM
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Kinda sounds like it maybe has a sheared flywheel key. Have you hit something that stalled it lately (before the problems)?
Old 08-15-12, 02:45 PM
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Join Date: Aug 2012
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Thanks for the response, however I do not believe that anything was hit lately that would have sheared the key. I will look and see, but do not suspect that as the issue.
Old 08-15-12, 02:56 PM
Join Date: Oct 2011
Location: USA
Posts: 433
Did you clean the main jet that holds the float bowl on?? It has two holes on the side and one down the center of it,,,,also you may check to see if the intake manifold is loose and or cracked. Good luck.
Old 08-15-12, 05:51 PM
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Join Date: Aug 2012
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Thanks mowerdude, I have not torn it apart to the point of the intake manifold yet to see, but that is a good idea! And yeah I cleaned and recleaned the bowl nut and all the holes in it.
Old 08-25-12, 12:31 PM
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Join Date: Aug 2012
Posts: 4
Took this rainy morning to tear all the way into the mower and figured I might as well check the head gasket. And sure enough, it was blown in two spots. Looks like one was more recent than the other. So off to get a new head gasket, might as well add an exhaust gasket to the mix while I am at it.

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