https://youtu.be/uV5H3kOkVfg detail video here!
additional detail, I replaced the red power starter key, original one broke in half, and I did accidentally put engine oil in gas tank, and I drained all or almost all by heaving it tilted almost upside down for an hour or more ....
more info about the law mower is here. https://www.searspartsdirect.com/model-number/247377440/0247/1500600.html
Would like to know any hint.