Was told once that you can tell condition of jet by rpm, so was wondering what the avg rpm was for a 19' 3-stg after getting on plane. Im sure there is alot of variables but just a general idea what people are seeing.
I have an 18' Almar Jetstream with a 351 ford engine and hamilton 3 stage jet. Have owned this boat since 1985 so I have a pretty good feel for when the impellers are worn.
I usually cruise at 3600 rpm which gives me around 30 to 35 mph, depending on how loaded the boat is.After a few years I notice the speed dropping on the gps and the rpm's needing to increase to keep up mph. Unless you have had your boat for a long time I think it would be hard to tell what shape the impellers are in other than looking at them. If you can see much daylight between the blades and the tubes, you probably need to rebuild or replace. Hope this helps. Email me if I can help further.