I was fortunate enough to get a copy of the 1990 Mercruiser service manual when I got my boat.
While thumbing thru it, I noticed that it says to apply the bellows adhesive and wait for it to dry before installing the bellows.
I have always installed the bellows while the adhesive was still wet.
Is this info out of date? Anyone wait for the adhesive to dry first?

Looked in a 2003 Merc manual and it says the same thing. Humm..

Bellows adhesive is like contact cement. After coating both surfaces, let it dry to the touch before installing.

Dito, I always used it while it was still wet....

i let it tack up a little,been working for me.

will add that it is more important to install any bellows to a very clean surface beforehand using bellows adhesive or not. A lot of times the flange(s) will have mineral deposits or Aluminum oxide built up or the paint peeling off of the flange area itself. We have never let the bellows adhesive dry before installing. It tachs up somewhat quickly though .