I have an O-290-D2 on my RV3. The ignition timing is currently set up at 25°. I recently noticed in the Lycoming operator’s manual that it should be at 18°. The engine seems to perform well enough, but I’m wondering why the D2 and D2A are the only two engines in this series that have a different timing setting. Can someone educate me please? Also, is there any reason why I should not leave it alone? I.E. is there some kind of hazard in leaving it at 25° instead of changing it to 18°?
Thanks for any advice and/or information you can provide.
Thanks for any advice and/or information you can provide.