Here ya go. This is a 40 hp, but the idea is the same. You won't find a kit anymore, so just accumulate the parts and go for it. Find a bypass cover with the 3 pump mount holes from a junker 35 or 40hp. i-boats has the pump. fuel connector and hoses are everywhere. The i-boats pump has the fittings at a different angle than the one in the picture, but who cares?
In a thread further down about a 58 18hp Johnson, tmcalavy mentions Engine, Blade & Prop in Milwaukee, wi as having the conversion parts for an 18. Maybe they have what you need also.
