What spark plugs are cross refrence for a champion plug RN4C

If you type this question into google you will get several equivalents. You may find questions like this are more quickly answered using google rather than waiting for Fixya answers

Champion L82C = Champion stk 811
Bosch W3AC, Bosch stk 7528
AC Delco 41F
Accel 156

NGK B6ES = Champion N5

Spark plug cross reference

take the plug to an auto parts shop and their catalouge for champion will have cross references for other makes of plugs

Chainsaws Other models
NGK will be 0.7 or 0.6
source page 14 of 121 pdf
http://ngkntk.co.uk/wp-content/uploads/2011/03/horticulturalcat2013.pdf
B-4 3210 0.7
Thrifty 3010, Swifty 3014 B6S 3510 0.6
Garden Tractors Garden Tractors BR6S 3522 0.6
Grass Mowers B&S engines BR2-LM 5798 0.7
Clinton engines B-2 3110 0.7 Model B B4-LM 3410 0.7
Tecumseh engines B-4 3210 0.6

Find a spark plug cross reference chart online and lookup your application.

30wt oil, probably a Champion RN4C plug. Could give link to a manual if part / model number of generator was provided.

Check the "cross reference:
Champion / NGK
A6 / DR8EA
A6G / DR8EIX

Visit here 1986 FERRARI 328 GTS 3.2 V8 F105CB FI

Good luck.