Hi there, Been working on the boat, getting her ready for the season. Yesterday when idling to the boat launch, I noticed that the engine was running a bit rough. I then realized that my max rpm was 4500 wide open. Also, when loading her onto the trailer, she did not have enough power to get her all the way up to the wench. This morning I decided to pull the plugs and troubleshoot the distributor and stuff. The first plug I pulled had the side electrode broken off. My question is, How much power can one expect to lose running one cylinder down. I have an 07 Mercruiser 5.0. I have pulled my other plugs and they all look real good except for the last 2 that are going to be a PITA to get to. Do you think replacing just the one broken plug will restore my power issue?