I've browsed the forums and Internet for days so bare with me. I have a 89 Baja 250 sport. 454 mag with bravo 1 no captains choice. When I put the boat in the water I gets a lead from where the lines for the drive go through the hull. I understand there is a block off plate there. I tightened all four screws about 1-4 turn or less. I also siliconed from the outside around the plate through the drive. I filled the boat up with around 40 gallons of water but did not see a leak on the outside. Shift cable bellow is tight. Drive bellow has some dry cracking in the valleys of the boots but doesn't appear to be in bad shape.

I won't have an opportunity to put it on a ramp and back it in slow so in looking for suggestions or tests I can do. Motor on or off has nothing to do with the leak and I didn't see any leaking around the transom plates When I filled the bildge I only submerged where the plate is and stopped.

Any help is appreciated

Ayuh,.... Welcome Aboard,.... If the bellows are dry-rottin', they not alright, but in need of changin' out,.....

As for the water leak, like any other leak, ya gotta make it leak, then look to see where it's leakin',....
No easy way out,....

Use a digital camera to put yer eyes, where yer head won't fit,....

If it is leaking it is from one of a couple places.

Shift Bellows
Drive Shaft Bellows
Block Off Plate (probably the least likely)
Steering Pin (Swivel Seal)

Keep in mind those bellows are 5 year maintenance items and should be replaced. Once they leak you will also take out the Gimbal bearing (almost instantly if you're salt water) so a little prevention is worth the time.

My guess is steering pin in the top of the Transom Assemble and that's why you didn't see it. Search JR Marine. He has a solution, or you can just yank the motor out and fix it.

You can fill the boat with water and see where it comes out when on the trailer. Of course this only works if the leak is below the engine starter. Put as much water in the boat as you can without flooding anything and if it doesn't leak you know the leak is above the water line.