38 SCweighs 9500lbs as opposed to 38 lightning at 8200lbs. Call Marty Boesinger at Fountain, he is the rigger and always willing to help with setup info, props, trim etc. 24's sound a little small for those motors.

Well , we didn't get to figure it out .
The weather was bad and we only went out once and had 2 small kids on board sleeping ! :D

Maybe next week. I am sure it isn't trimmed right ,and I would think it needs bigger props . The boat runs realy well and he is happy with it as is but I know he would be even happyer if we got it dialed in right !

Since there was no way to do this test , I didn't pay much attention , but I think his indicators start at 1 and go to 7 or 8 is that normal on a fountain ? Most i have seen have negative and positive numbers ....... Thanks

Been there done that. Assuming this is a sport cruiser, I can help. It sounds like he's going through the same progression I went through with mine. Started life w/ 502 MPI's then 510's with 250's on top now 545's w/ 10-71's, Whipple chillers, dry stacks and BMax drives.

Trim the boat and then trim some more. Depending on the year hull and drive setup, I would think 6 is still deep - probably 7 plus is the trim answer but I don't think that's where the problem is. If he's around 600hp, the boat changes from a slug with its nose in the air to a performance boat.

I'd really need to know how the boat is setup before I could give a better guess at the problem. pm me your number - i'd be glad to help.

Why the 4 blade?
 

Mitch is getting at something here.

Why the change to a four blade???? Did you change the x? If not then he has no need for a four blade. He's getting to much prop in the water. Go with a three blade and I bet you will see better gains. I'm making the switch right now.

Turning a 27 4 blade topspeed 78.7 on GPS at 5350rpm
Turning a 30 4 blade topspeed 80.6 on GPS at 5000rpm
Turning a 25 3 blade topspeed 79.1 on GPS hitting the rev limiter.

Right now I'm looking for a 27 or 28 3 blade to try.

If this is a sport cruiser, getting on plane is very difficult with 4 blade 23's. With full tanks it is almost impossible. Full the boat is going to be 11,000 plus. I
agree that he has the wrong prop but I think there is sonething else going on.
When I had 650's I was spinning lab 26's in fresh water and 28's in salt but I'm not sure that the prop is the entire problem. WIth this power and 24's, he should be spinning around 5500 and running upper 70's on gps.