I hate to be a spoil sport, but I just pulled of the head-covers/water jackets off of my motor, and I can tell you from my newfound experience, that once you have a large build up of crap in there, flushing with vinegar is pretty useless. (This motor is used in Salt water)
Even with the head covers off, I had to scrape and brush all of the "calcium looking" buildup out and that was after soaking several times in full strength CLR. This was in a 1992 150 that I bought used. Hopefully, your vinegar flush didn't break off any chunks and obstruct any passages. I had tiny chunks in my passages.
I tried the Saltaway Flushing prior to pulling the heads with no positive results. After the heads were off, I sprayed full strength vinegar around the cylinder, and it didn't even remove the mud like substance inside. I had to scrape it out. The buildup just laughed and said " Is that all you got!! "
edited to say W.O.W !!! I just noticed this thread started in 2008 !!
Last edited by classic73montauk; 07-11-2010 at 09:48 PM.