if i get a one engine outdrive boat
can i put later 2 two engines ?

It depends on the boat but it is an expensive under taking.

how about a Bayliener ?

Depends on the model and the width.

Bayliner 2855 ciera 1993

It would not be worth the money to do. Better to sell and buy a twin when you are ready. That boat would perform better with a Bravo-3 or similar type twin prop outdrive and a little more power.

thank you all

There are no stupid questions...

Just stupid people who ask them!

OUCH! That'll leave a mark

imco did this a few years back,in a high performance package,i will find the issue of powerboat and post it .