from my understanding, they come with the new manifold, they don't have separate part number... and we couldn't find anybody selling it. Interestingly, I and another member here also replaced another manifold on his 280 this morning. He made it looks so easy....
Yeah, removing and installing is fairly easy, hour out and hour back in. However, doing it right is another thing.
That fitting in the photos is very subsceptable to breaking. There are two of those, but the one on the passenger side is the most vulnerable to breaking as the attached hose reaches its limit as you're lift out the manifold. The one on the driver's side attaches to a sender that can be removed from its mount, thus preserving that fixture. Bottom line, the plastic gets brittle and breaks. If a piece remains in the manifold, use a drill and then a bolt extractor to get it out. Mine also had a piece break off in the hose and same deal, drill and extract.
I think you're right, I did not get the injectors/rail properly seated, resulting in a leak and lean running on the cylinders involved. I ordered a set of upper and lower injector seals and this time will use some synthetic motor oil to slide them into the old girl.
As to my existing problem of misfiring on cylinders 1, 2, 3 and 4, plus lean running smell from the exhaust, I really doubt that any ignition coils went out during these repair efforts. I didn't touch the coils. I'm sure it has to do with the injectors and I doubt that they went out either during my efforts. So that leaves properly inserting them as you've pointed out. I was wondering whether I got them in properly on the first go around when I had misfires on just cyclinders 1, 2 and 3. Now it has increased to 4 cylinders.
If this solves the problem, then my purchase of the manifold was unnecessary. So I will have the extra fittings and the actuator available.
I guess I've been working more on my boat diesels and truck diesel and really have not come down the learning curve on these modern gassers. Owning Hondas will do that to you. 0