Re: Mercruiser 4.3L, I/O 3000rpm at full throttle till plane
Sounds like you lost a lot of power, could be anything from misadjusted timing to a freeze-damaged engine to bad gas to.... you get the idea.<br /><br />Start with a compression check, pull all the spark plugs, then one by one attach a compression guage to each spark plug hole and see what it reads as you hit the starter and crank the engine. If you see one cylinder lower than the others by a good amount you likely have an internal engine problem. This will at least get you pointed in the right direction. If you're below 100psi or so across the board you're also pretty low. <br /><br />Don't rev your engine that high in neutral, you're asking for problems, briefly or not. Just warning you.<br /><br />Another thought, have you added a lot of weight to the boat, especially near the back? My 19 footer performs well typically, but yesterday I was letting someone else drive, and my friend and I (both big guys) were sitting all the way in the back next to the engine box, and it was strugging to get on plane when usually it's a piece of cake. We moved up to the back to back seats and it was much much better. You're probably thinking my boat is a dog, but keep in mind my friend and I add up to a bit over 600 pounds. I'm 290 alone and he's about a foot taller and wider than I am..... haha..
<br /><br />Let us know what you find on the compression check. It's about the best place to start. You can pick up the guage at any auto parts store if you don't have one already.
