On Fri, 23 Feb 2018 09:43:12 -0800, ultred ragnusen
wrote:

I should note this is a California set of engines, so there are no set
screws for the idle speed.

You guys have "spark arrestors" on engines. I have read they need to
be removed an cleaned. Try that? Something about carbon build-up in
the arrestor. Maybe the engine is not exhausting burnt gases?

Surging engines often is because of improper air / fuel mixture.