4.3 engine stalls

Stalling is a nuisance, but I'm afraid it may lead to other problems. Recently bought a 1997 Bayliner Capri 2050. Replaced the engine with a remanufactured long block 4.3 V-6 and real nice Alfa One Gen 2 from an 07 wreck. Put on a remanufactured Rochester 4bbl and a remaunufactured alternator. Switched everything else over. All runs great except for two problems. Here's the average day...........Back the trailer in the water, engine fires right up. Back the boat off and its fine till I hit forward. That's when it first stalls. Starts right up again, and idle over to the dock. Put it in neutral, and it stalls again. Kids jump in and say "go fast Dad". Starts again and slip it into forward. Idle away and hit the throttle. Takes right off and planes out, everythings good, but can't get more than 3200 rpms. Book says 4400 - 4800. Then slow down and stop so the kids can go tubing.....engine stalls. Do this several times through the day, then go back to the dock. Engine stalls several more times maneuvering aroung the dock and onto the trailer, but only when shifting between forward and reverse, and sometimes when just going to neutral from forward or reverse, even after a long idle. The idle is set at 650 (per the book). I tried raising it a bit, and that seemed to help, but the clutch and gears sure don't like it. Seems like there's a dead spot on both sides of neutral where this stalling is happening. Shifting quickly past it seems to help with stalling, but again, it grinds too much. Sure would appreciate your help! Thanks for reading.

Re: 4.3 engine stalls

could be shift interrupt switch activating improperly due to a worn shift cable causing the dying while shifting issue

could be tune-up related, did you replace plugs, wires, cap, rotor, fuel filters, etc...??

have you adjusted the idle mixture screws on the carb??

check timing??

Re: 4.3 engine stalls

Sure sounds Like shift interrupter, get the manual and carefully adjust the shift mechanism. I'd bet that's the problem.