I use 85 Octane, 50:1 oil mixture, and sea foam with every gas fill up. I took the boat out Friday and the thing ran like a charm with the new plugs...go figure. Plus I caught my second PB LMB
LIVE AND LEARN.
It's unnnecessary to use solvents continuously in a clean, good running engine. Fresh gas and a good grade of 2-cycle oil is all that is needed -- cleans and lubricates.
87 would be the correct fuel. Seafoam isn't hurting anything, but it's not really helping either, it's best to eliminate all the variables when possible.