AVB, starter fluid, being ether, is a lot more volatile that unleaded hence making it easier to combust under less than ideal circumstances. Opening the plug gap will create a more intense spark, as long as you don't open it too far, and is particularly useful in low compression situations. I thought these engines had the resistor inside the spark plug cap but perhaps they don't. Look inside the cap, if the brass part can be unscrewed as in some Honda models, there is a block of carbon behind it which you can replace with a similar size piece of metal.
