07 VLX Block Drain Plug

[SGillin]

I went to winterize my boat and got everything drained properly but when I went to reinstall the block drain plug/knock sensor stud on the starboard side I cannot for the life of me get the threads of the plug to grab on the threads of the block. I tried using some WD 40 and a battery terminal cleaner to clean both the threads on the block and plug, but no dice. 
 

I was reading on here that some people have chased the threads with a 1/4 x 18 NPT tap. I went to Home Depot and bought what I thought was a 1/4 tap but it’s way too small. 
 

Anyone know the appropriate tap size for an 07 VLX (monsoon 340)?

[Soon2BV]

Did you get a 1/4" tap or a 1/4" NPT Tap.  Pipe threads are different.  a 1/4" NPT tap is about 0.54" OD. 

[SGillin]

This is what I bought but doesn’t look like NPT https://ibb.co/1f8dzQV
https://ibb.co/C1MMND3

[BlindSquirrel]

That’s not the right tap, it says “SAE”. It appears you can get the correct one at Napa.

https://www.napaonline.com/en/p/BK_T302?cid=paidsearch_shopping_dcoe_google&campaign=GSC-Tools-Equipment&campaign_id=8553470562&adgroup_id=107047174069&adtype=pla_with_promotion&gclid=Cj0KCQjw-pyqBhDmARIsAKd9XIMs0F0I4tgI7OKw-tTqWTWkwNIAchE_2cNfrWhapmKH06JlTQ3mbuwaAu0YEALw_wcB&gclsrc=aw.ds&gad_source=1