You won't like my response but many of us have spent many $1000's on carbs very similar to yours. It is highly unlikely that you are ever going to get these carbs run right in a marine pleasure application. IMO, you will be $ ahead if you sell these now at a small discount and long term you will save $, frustration and hassle. The new Holley Ultras will run perfect out of the box with no changes. I know as I made the same errors.....except we went to 4 different carb gurus before we figured out most/all know little about the idle circuits needed in a marine carburetor. The big hurdle is the ability to get the boat to idle in and out gear without stalling or the risk at a high idle of sticking the clutches in a Bravo drive.
The good news is many carb tuners are masters at picking up couple of .1's drag racing :cool-smiley-011:

I wouldn't give up on the that easy. I know of a few boats running around with AED carbs without any issues.

factory 525SC's don't idle that bad, I redid a pair in a 35 fountain a fews years back, I did later lock the dist and run 28 deg, helped it a lot..

Mild cam, plus a roots blower actually can help the idle/tame down the cam so to speak.

I can see where you locking the timing on a 525SC would help it idle. Any reason you pulled 7 degrees of total advance from it up top?

these 588s like fuel we set the idle in the drive way get to the lake but it in gear had to work the throttles up and down we got the ultras out of the box ran on the stand not in the water sent them to bigs performance open up the air bleeds gotrid of power valve he got rid of the third circuit are for corners are open 2 -21/2 turns out timing at 34 we idel at 900 1000 ingear 500 to 600

The owner loves to run WOT for long periods and when I did a 525 clone a few years back was talking to one on the blower guys @ weiand he recomended 28 total using the 177 blower, I played with more timing and saw no increase in speed to stayed with that #, only running 28 with the procharger deal know..but as soon as I get AFR dialed in now that I have a working wideband, going to see if more is a plus...

Got In The water to try it. I got it to 24deg of timing at 1000rpm and 36 total When I pop the boat in gear it drops instantly to 500rpm. And it will still run but seems it is ready to stall out any second I need to get a little more sureness out of it that it's not going to stall. I played with the mix screws but really didn't Change anything. Any ideas ?

Do you know if your idle jet is in the upper or lower position? They idle a lot better if they are in the lower position. Also if your mixture screws are not having any effect you have too much transfer slot exposed. You only need about .020 of the transfer slot exposed. If it wont idle with the throttle plates closed that much you will have to get some bypass air in it. Mine has 10/32 set screws up by the air cleaner for that. Only do one thing at a time!

I'm not sure where the idle jet is. I am doing all my idle Rpm adjusting off the primary side of carb. That's what AED said to do on their carbs. U think I need to drill holes in the flaps to get some air in there and that will let me close up the primary?

Another way to add air vs. drilling the throttle blades is to drill and tap some jets in the airhorn. Adding air will help, but....