"This is the problem, Leo: you
"This is the problem, Leo: you cannot just get that "little flapper" from Volvo Penta: you have to buy the whole "exhaust outlet" (part 4), and the real price is much higher than the $20 listed at the Volvopentastore site. If you search the forum, you will see this has already been debated and the solutions are: 1) make your own flapper in whatever suitable material you can find (I have done so in the past); 2) don't install the flapper and risk to hydrolock the engine when you go on reverse or stop suddenly; 3) buy a new "exhaust outlet" at Volvo Penta prices; and 4) buy the aftermarket exhaust bellows with flapper.
The choice is yours."