Does your boyfriend use marijuana regularly? Excessive (daily, regular) marijuana use impairs semen production, resulting in a yellow-tinged but clear ejaculate. (I don't know about "bright" yellow, but it's definitely yellow.) Such ejaculate is still gel-like (until it breaks down, anyway, in a few minutes), but it's pretty transparent, since the sperm cells are completely absent.
Then again, perhaps your boyfriend has some sort of yeast infection, or perhaps even a more serious problem. It's difficult to say on limited information.
As for slower ejection, that's probably related to an underdeveloped or weak PC muscle. Go to Google and search on "Kegel Exercises" for information.