Ok where to start......been a long day... 1991 Force 120 hp. Had the powerhead rebuilt in 2008. Changed the spark plugs yesterday (have changed them before, just not sure if they were clean) and noticed the plugs in the bottom to cylinders were kinda clean. Didnt really think on it to much. Took the boat out today and it would not get going, only about 10 mph. My buddy and i played around with air-fuel mix, and checked for spark. Took the boat back to land and checked the carbs, both bowls were full, top 2 plugs were wet and dirty and bottom 2 were almost completly dry, took off carbs and made sure all holes were clean and clear. We also switched carbs. Took out reeds and checked them, all were fine. Also switched around the reeds. Put the boat back in the water, still the same problem. Decided to take boat back home and pulled off the cylinder head and seen that the bottom 2 cylinders were completely clean, and have no signs of ever getting fuel. And thats where we are stuck, we got a strong feeling that its a vacuum problem but cant figure out where to go from here. Not sure on how the engine creates vacuum, from us ripping it apart it looked like its made in the crank case. Any info or ideas would be great. Sorry for the long post just trying to give all info. Thank you all
