Re: There was no petcocks on the manifolds
There is a difference between the 91 and the 88 models, the 88 is the one piece batwing, that one has the normal petcock, the 91 they changed to the 2 piece like the later model Volvos, those have a rubber cap on the end that can be removed to drain.
go on to 'www.dougrussell.com
look in OMC/Volvo parts, there diagrams that will make it clear.