Old motor, throttle+idle issue, runs with ears @ high idle, not in water

[kevinlabrie]

So here's the scoop. Bought a motor from buddy with a blown timing belt. 1971-2? 50hp 500 2 stroke thunderbolt ignition red stripe. Ad said new belt and water ready......but upon tearing the motor down, realized the distributor bearings were siezed. Replaced bearings and rebuilt distributor. Distributor button is keyed to the timing pulley and both that pulley and the flywheel have factory timing marks so im sure im okay there. tore the carbs down and cleaned but not sure if i set the jets back exactly right, (i counted rotations out, tried to set back in the same) having a hard time finding content on the net to find proper specs. checked fuel pump and water pump, working fine. so i rebuilt the motor and she turns over beauty with full throttle and no choke. i can throttle her back a bit, but cant get the low RPMs to engage the gears. (actualy i did at high RPM, and seem to have acceleration control but i know this is not good). took it in the lake to try it out and still starts out water but when it under load i cant turn it over. I started it trimmed up, full throttle, and sunk it and it continued to run but when i touched the throttle it died.i think my problem is in the carb tuning and the spark advance timing. Im trying to re-do the carbs properly, just tore them out 30mins ago (any free manuals for specs??), and found a good link for setting spark advance and idle/throttle/carb stops. new spark plugs, new gas tank, new battery. got my blood and sweet in this one, need help. Oh just got back in from the driveway and found a blown out hole in the block, i think on the bottom cyl, and and arm on the shift selector has been sheared off. anything will help