I just got a 1979 belmont jet boat, it has a 454 bb chevy with berkeley pump. it runs great just been siting for years. I changed the oil and filter,cap,rotar,plugs and went over all the basic stuff and it runs great. i took it out for the first time and found out the intake manifold gasket was shot,so i fixed it and it runs strong...BUT when i hit it wide open it goes good for 20 seconds or so then the rpm's drop... goes from 5200 to about 4700 still wide open and slows down a lot and runs a little hot, some times it goes to 4000 and gets a little too hot(has not got hotter than 210-220) seems to me thats a little too hot when going fast...its almost like i sucked up some seaweed or something,but when i go about 10 mph it cools down then i can get on it agen for just a little bit then same thing happens. has anyone ever had this problem??????
thanks for your time