The adjusters are set with an alignment tool. They are for adjusting engine crankshaft pitch and angle to prevent wear or failure of the gimbal bearing. If you do not have the proper alignment tool and are not versed in it’s proper usage, it is best to take it ( the boat) to a professional. Install the engine, bolt it down, and take it in to have it adjusted BEFORE reinstalling the outdrive. Tell the boat shop you would like them to align the engine. Failure to get this adjustment right will cause severe damage to the coupler, gimbal bearing and u joints.