I have a Ranger 375 V I/O that had the stock V-6 replaced with a Vortec V-6. All the carbuation and ignition off the stock engine was put on the Vortec. The guy who did it was good at what he did. The guy I bought the boat from said it ran very fast. It has been sitting for almost 2 years before I bought it. I can't get the boat to take more than about 2/3 throttle. It starts easy, idles smooth but is very sluggish comming out of the hole. Runs just god enough to get on plane but if you try to give it full throttle it just boggs down. Plugs are black but it seems to be running out of fuel. I am a mechanic by trade and have gone through all the basics, ignition system, carb. kit, timing etc. I have heard that overfill of crank case oil can cause such a problem. I could really use some help here since I have been working on this thing for about 3 weeks now and have made no progress.
