kvscarab38

I have a 38 scarab kv with ssm IV drives with 2" spacer and a 18x29 4 blade cleaver prop with about 550hp it seems like it takes forever to get on plane about 30mph do i have too big of prop not enough hp not enough k plane 380 or too deep in water or just dont know how to drive once boat is on plane it runs great just maybe not fast enough 65@5000. To get on plane just set rpm at about 3000 kplanes and drives down and wait for props to hook up.
Ps straight bottom hull.
engine originally was 1987 575 hpmercury racing but has been rebuilt with hydraulic roller cam do not know which cam it has was just guessing on hp. Its a 540 tall deck with team g intake and dominator carb. Its supposed to be original except for full roller hydraulic cam set up.
and i'm not sure on x dimension also has stelling extension boxes and headers

rv

Change to 5 blade prop. I have 5 blades and tried a set of 4 blade once and it took forever to get on plane.

Chris Sunkin

Sounds like too much prop, both diameter & pitch. If you truly have 550 hp the boat should be going faster than 65. 5000 rpm is low for even a stock 454. If you have 550's, it ought to be topping somewhere in the 5800 rpm range or higher. Set up right, you should be able to pop up easily with tabs & drives set neutral.

Where is your x dimension at?

kvscarab38

Thanks but engine is not 454 i guess i should have included that I'll try to edit 1st post engine originally was 575 mercury racing but has been rebuilt with hydraulic roller cam do not know which cam it has was just guessing on hp. Its a 540 tall deck with team g intake and dominator carb.

Chris Sunkin

What drive ratio? What's the X?

That's pretty big power- should be somewhat over 550 hp. should be at least 650. And be able to spin 6K all day.

kvscarab38

not sure of x dimension but I'll post a picture maybe you can get an idea the drive ratio is 1.5

kvscarab38

Maybe this is a better picture.

MOBILEMERCMAN

A 38 should come up pretty easy. It should turn more once up like others have mentioned. Aside from what rpm it runs once up some boats with a hot set up need a hand full of 4500 or 5000 to get up. Try it with tabs down about half way. gently push forward throttles until they break loose and moderate engine speed from 3000 to 4500 until they grab. Maybe 2 or 3 times will bring it up. Don't let them over rev and only advance to higher rpm for a second or two. I would also suggest checking to see if the water intakes are in line with the props. Can't tell by the picture.

kvscarab38

water pick ups are in the center are they to close in line with props picture enclosed.

MOBILEMERCMAN

The pick ups could have been installed in a better location but, moving them may not completely solve the problem. Some boats need some finesse to get on plane. Nice hardware hanging there has it always had that set up?