New guy here, 13 1/2 hp B&S no compression

snorky1 said:

put the old rings on the old piston and with a feeler gauge measure the gap between the ring and the piston land, there are min and max allowances for this and if the are too great the ring can snap and if too thin hang on the cylinder wall.

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bertsmobile1 said:

Did that piston come from an authorised B & S dealer of from a online retailer on evilbay / amazon etc.

While there is some logic in that shoulder it would make accurate machining of the pin hole almost impossible as you can not hone all the way to a shoulder.
I have a sneaky feeling that piston have have it's origins elsewhere.
It is the sort of thing I would expect to see in a counterfit engine.
If it is genyine then one side of the piston pin should be square on the end to do against the clip while the other end would need a substantial chamfer at the end to compensate for the zone where you can not hone.

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Dryan said:

I bought the mower from home depo in 2006, used it about 6-7 years to cut my moms field (its not grass) mower sat for a few years , son in law got a piston and rings for it but did not install, thats how I got it, the piston is in a B&S box that he got from dealer PISTON ASSEMBLY 797009 Date Code 1441,DD025.

The light colored piston in the picture is what came in it when I bought it, the piston is a little different than the replacement I was given to replace.

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