Has any outboard manufacturers experimented with pre-chamber fired outboards?

One of the engines I work on, Cat G3600, uses a pre-chamber to fire the lean mixture in the cyl.
The air/fuel mixture is so lean in the cly. that it cannot be spark fired. So they use a stoch mixture in a prec-chamber with ports kinda like a diesel injector to ignite the air/fuel in cyl. Has this been tried in outboards?