Here is some help for others out there that may be running into the same problem I had. I have a 5.0 litre OMC 1994. The boat for the past 2 to 3 years has been running at about 3300 rpms at wot. The correct rpms would be 4000 - 4400. mechanics had rebuilt carb, flushed entire fuel system. compression checks, tune ups, even cheated with changing the prop to a 17 instead of 19. Nothing was working. Over the weekend I blew a lower exhaust hose. while replacing it. noticed that these pieces called "flappers" where missing. They prevent water from entering engine in rough water conditions so I was told. Found them at the "Y" intersection of exhaust, both plates were restricting flow of exhaust and water from engine. Chipped them out, took the boat out and now I am happily pushing 4800 rpms. Time to put the 19 back on.
Just thought I would pass this along to others, If your losing RPM and fuel, spark, and compression are good, It is wise now to check the exhaust system for some type of blockage. it took me 3 years, 6 mechanics, and some money to find the problem. I hope this helps out
Just thought I would pass this along to others, If your losing RPM and fuel, spark, and compression are good, It is wise now to check the exhaust system for some type of blockage. it took me 3 years, 6 mechanics, and some money to find the problem. I hope this helps out