Re: gap champion l77jc4 johnson 85hp?
I first "discovered" these plugs back about 1970, while going crazy trying to make the 60hp loop charged motors run right. Replacing the original surface gap plugs with these worked miracles.
The reason for reducing the gap is that it requires less voltage to jump across a narrow gap than a wide one. Now, there are a few reasons that may be desirable. First, your ignition system may be incapable of producing enough voltage. Second is, todays systems can produce plenty of voltage, but the actual developed voltage is whatever it takes for it to go somewhere---preferably across the plug gap. But if the path of least resistance is somewhere else, that is where it will go. If that is through the side of the coil, it will burn a hole through it. In other words, less strain on the ignition parts.
Bottom line is a wide spark may ignite the fuel more reliably than a narrow one. But if a narrow one is all you need, no point in putting more stress on the system. Just my 2c.
