Ok...Just got off the phone with NGK support.Feel free to contact them with any spark plug questions.
http://www.ngksparkplugs.com/About_nGK/contactus.asp
The product support represenetive says that the 86' V4 90hp Johnson can run the BR9HIX plugs and even said his book specifies a BR7HIX or BR8HIX specificly for this engine.Upon cross referencing the heat range,He also stated these are in the same heat range as the QL77JC4.