Small Engines (Lawn Mowers, etc.): B&S 21 HP model 407777, psi cylinder, vacuum gauge


Question
I have a compression tester.  Motor type is 0121E4, Code number is 021121YG.
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The text above is a follow-up to ...

-----Question-----
Ok,  plugs have an oily black build up, mower emits white smoke when engaging blades, mowing up a hill or cutting taller grass.  Engine oil is SAE 30 by B&S.  I tune the mower up each  spring with B&S kit.
-----Answer-----
The engine is consuming/burning oil. A leak down tester is probably the best tool to check the condition of the condition of the engine.  
A compression gauge will also provide a good indication of engine condition.
Roughly, how often do you use the mower and for how long?
Please send the type and code number of the engine.
Do you have access to a leak down tester, compression gause of a vacuum gauge?
Let me know.
Eric

Answer
Make sure the dipstick o-ring seals are sealing.  Older o-ring tend to dry out, not seal which caused a slight vacuum leak in the engine...this will lead to oil burning.

If you check the compression, both cylinders should produce a reading within 10% of each other.  For example if cylinder is 100 psi, cylinder 2 should be 90-110 psi.
Let me know what the compression is.
Eric