SB

iTrader: (1)

A propeller will spin fast with more hp....unless the load against the motor will not let it do so, ie: the boat itself just does not want to move any faster.

Impeller's are totally different. They are more like a torque converter or better yet, a water brake on a dyno.

That's all I know. Absolutely no jet experience what so ever other than reading basics on them.

1 2 NV

well its been a long time and i have an update. i found out during my trip that my impeller was F'd. in swift water it was cavitating. thats not the main issue though. so i had no clue where to begin to solve my cavitation problem. was in the impeller, stator, other. i had no idea where to start.
the impeller was just worked on so it should have been good. i had that low RPM at WOT issue because the motor wasnt making enough power etc. so i was able to get 2 different impellers to test yesterday. i found one 2 sizes down and the same one i have. the downsized impeller allowed my boat to turn 4800-4900. i havent looked at the datalogs to get exact. in the whitewater once it unloaded i was screwed. it didnt have enough push to get my boat going in the right direction once unloaded. i also got to try the same pitched one as i currently have. i just did a speed run to see what RPM it would run. it ran exactly the same as my F'd up one. you could feel the difference in push though. so it appears i need the one in between these two.

GPM

If you actually knew where the cam was placed in the motor, you might try advancing it another 4 degrees before changing it. By doing so you will lower the power range by several hundred rpm without losing your peak HP.

Scarab28

I'd try running a "C" impeller. Jets like big block torque.

1 2 NV

i cant remember where the cam was installed. i think it was installed exactly as need be which was advanced.
its a hamilton pump, not a berkley, american turbine or scott.

GPM

If you didn't use a degree wheel it's impossible to tell. Lining up timing marks doesn't mean it's right.

Baja Rooster

iTrader: (1)

On my motorcycle engines I've found the cam timing marks to be off by as much as 4 degrees.

1 2 NV

my builder put it in. not me.

tunertech

talk to Duane at hi-tech performance he is the best in the country when it comes to pumps. I've worked with him for years. He can steer you properly