Craftsman 917.28712 runs fine but white smoke

[jlatenight]

Removing the rocker valve during the leakdown test will show more air escaping from the push rod galley then the dip stick tube.

I already returned the leak down tester, or I'd do a test with the rocker removed so valves stay closed, and with some oil in the cylinder. Might be worth me getting another one. There was definitely air noise from both the OHV cover and the dip stick.

engine hanging up on the compression stroke when cranking

It doesn't have any problem starting up.

oil is blown thru the breather tube and the carburetor inhales it

There's no sign of oil in the breather. Maybe the breather valve is blocked? I could take the head off and check the head gasket again. I didn't see any sign of it being blown on either gasket I replaced and I looked really close on the spot between the cylinder and valve galley.

I would bet that it's actually the BLUE oil smoke since it's gulping oil.

I would think it would be blue too, but it looks pretty white to me. My neighbor who's a gear head commented it's white and not blue. Not sure how that could be though.

I usually just find a good used old model Briggs

The tractor itself is in great shape. Garage kept. Is there a cross reference for which motors would be compatible? Is it just the shaft length and basic layout?

I saw you can put a vacuum gauge on the oil fill and see if there's any indication of positive pressure (I think)?

 

[mechanic mark]

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Hone cylinder with tool & replace rings with OEM B&S Part 791936, superceded to 594437 part #.

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[jlatenight]

Just wanted to report back that I replaced the rings and no more smoke! I put a new carb on it and it need a little adjustment. It's surging so I think that means not enough fuel is getting through, right? It's a brand new carb and wasn't doing it at first, but started to after running for 45min or so. Something in the main jet clogging it up?

 

[mechanic mark]

You posted Nov. 8th you installed cheap new carb.
https://www.amazon.com/Carburetor-Briggs-Stratton-792768-799727/dp/B07DSZ5Q63 Brand is not B&S OEM Carburetor here, cheap knockoff.

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https://www.amazon.com/Briggs-Stratton-594605-Replacement-Carburetor/dp/B0742Q2YK2/ref=asc_df_B0742Q2YK2/?tag=hyprod-20&linkCode=df0&hvadid=242053132289&hvpos=&hvnetw=g&hvrand=11627169084964895992&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1015319&hvtargid=pla-445325158219&psc=1

Above is Genuine B&S OEM Carburetor for your engine, lowest OEM price I could find.