The trim angle is sensed and an engine system such as the timing is adjusted to provide good running in response to the trim condition....http://www.google.com/patents/US4998521?utm_source=gb-gplus-sharePatent US4998521 - Ignition timing control for outboard motorAdvanced Patent SearchPublication numberUS4998521 APublication typeGrantApplication numberUS 07/493,893Publication dateMar 12, 1991Filin