How can I find what spark plugs?

I need for my boat without taking one of them out to take to the store. I thought I saved one but I didn't. I tried googling info about spark plugs but I couldn't get anywhere. I have a 1989 VIP Vision 1700 2.3L OMC Cobra. Help.How can I find what spark plugs?phone a good boat shop, someone will know off the top of there headHow can I find what spark plugs?I would call my nearest boat dealer and ask or go online to Vision boats and ask them