Briggs&Stratton 158cc

[jak52]

Have a Briggs & Stratton lawn mower brought new at Wallmart. Ran a few hours, then lost all compression.

 

[ILENGINE]

Get us the model number info for the engine, also how long have you owned the mower.

 

[shiftsuper175607]

Have a Briggs & Stratton lawn mower brought new at Wallmart. Ran a few hours, then lost all compression.

Did it come with oil in the mower?

Did you check it...or put some in? How much?

 

[jak52]

Did it come with oil in the mower?

Did you check it...or put some in? How much?

Filled with the break in oil. The piston/crank assembly works fine. Maybe a valve spring broke, or something happened with the cam.

 

[jak52]

Get us the model number info for the engine, also how long have you owned the mower.

961140004 09 Have had it for a few years, obviously should have returned it.

 

[ILENGINE]

Two likely causes of complete compression lose is the rod is broken, or one of the valve seats has came out and is holding a valve open. May want to remove the head and take a look.

 

[jak52]

961140004 09 Have had it for a few years, obviously should have returned it.

The exhaust valve is stuck open, and it isn't being held by the valve seat.