Well...I think that we are making progress. 4/6 carbs came off and the pair from our ill fated 1980 Invader went on. Lo and behold it ran just the same way as the 440 Invader, so this gave me some hope. Pulled the 4/6 carbs apart again looked through the passages, carb cleaner, air, cleaning rod - got shot in the eye with carb cleaner in the process - but did find that the orifice to the reservoir in the needle jet was gummed up. Everything cleaned and the carbs went back on. Now she seemed to idle but would not accelerate. A further check found that PTO side was running and Mag side is cold. Mag carb coming off again.