Both drives are shifting in and out of gear fine but right before the boat gets up on plane (roughly 3100/3200 rpm's) both engines /props will spin out and rev kinda like its in neutral. When I get off the throttles and slow down it will take off again but do the same thing right before getting on plane. Anyone got some ideas on what to check?

Sounds like they are cavitating. Make sure drives are tucked in, put your tabs all the way down. Also try holding a lower rpm longer to get on plane.

As Pure Energy said, the props are cavitating. Try advancing the throttles very slowly. Keep the rpms as low as possible getting on plane. Let the boat build some speed before you advance the throttles. Depending on the boat, you should be able to get on plane without going much over 2000 rpm. What type of boat and what props?
Eddie

This sounds crazy but try running the tabs all the way up and easying into the throttle. My boat will blow out everytime with the tabs down but rarely with them all the way up. I believe the tabs are lifting the props closer to the surface when you really do not need or want that.
Allen

Thanks guys. My tabs have been up everytime and drives tucked down all the way. I do ease into as slow as possibe everytime. The boat is a 1989 Century Ultra II, 27', twin 454's/330hp with Bravo 1 drives and Elite 1 24P props. Boat weighs appx. 6400lbs dry.

Did it do this before ? If not maybe you damaged a prop. Drive's in tabs down throttle up slowely bring tabs up as speed increases to sea conditions. Also are you in shallow water when trying to get on plane ? You might be starving the props if they are to close to the bottom of the lake.

Yes it has done it before but seems to be a little worse now. There are a few small dings in the props but not horrible and they were there when I got the boat and they haven't got any worse. Now my tabs could have been down a little before and I just didn't realize it. On this boat I haven't used the tabs much as I only run around for a few minutes then cove out and rarely run at full throttle, just cruise. And no, the water I was in was atlease 20-30' deep, no shallow water.

try a different set of props, some seem to cavitate easier than others.

I thought about that too. Now just to find someone local with some 24's. Now if I can't find them, should I try 23P or 25P props? Right now at WOT I'm running 4900rpm's on my stock 1989 330hp 454's. Thanks everyone for the help!

I would put the 24's back on it, 4900 should be ok but stay with the same setup so you know if it was props, if you change the pitch and it is worse you have not solved anything as you changed the setup. Sounds like props to me.