I have 1985 Wellcraft Gran Sport with twin 454 MARINE POWER motors(1996).
In October of last year I blew the V-drive on my starboard motor. I hauled engine out and installed a used V-drive. While the engine was out and at my shop the only thing I did is replace spark plugs, wires, cap and rotor. Dropped the engine back in and now for some reason it won't rev up past 2000rpm under load, it bogs down and backfires. At neutral works perfect, idles fine and revs up. Since that has been happening, I have rebuild the carburator twice, replace cap and rotor again, checked all wires, had the timing checked three different times by three different people and changed coil. It is still doing it. For the life of me I can't figure it out. It was working perfectly before the V-drive blow up. All it did was sit in my shop on an engine stand for six weeks until I found the V-drive. Any ideas?