Finally got my boat in the water for the 1st time yesterday. Launched the boat and was heading out at about 35 MPH at 3800 RPM, no boost, just a gently easy shake down run. After about 5 minutes the starboard engine just died. Restarted the engine fine and went to put the starboard trans in gear and it instantly stops the engine. Lift both outdrives, and the port spins in neutral, but the starboard is locked tight, prop wont spin at all. The boat is BBC twin turbo with Borg Warner velvet drives and SSM II drives. Both engine started and ran fine and shifted in and out of gear the day before on the trailer. The starboard trans always spun the prop when the trans was in neutral. I check the tans linkage position and it was fine. Can the trans seize up and not spin when put into gear? I also looked at the outdrive this morning and the lower looks fine. Did not hit anything. Drained a little of fluid out and it looked and smelt fine. The outdrive oil has 15 hours on it (mostly from last year) . When I got up on plane I wasn't doing anything stupid, no crazy 5000 RPM hole shots. Water conditions were smooth

First step I'd remove the drive and see. Sounds like your problem is there. Tranny's usually just spin freely and wont engage once they are smoked.

I agree, most likely the drive.

I just pulled my drive. The fluid is fine, but its not good when the chunks of metal are too big to mix into the oil and make it look bad. Mine locked up at about 4000 rpm this past weekend, shut the motor down and all like yours.

35 at 3800 rpm ... is that a mis print .