Motor help

[RaginCagin]

Alright, I have been out of comission all summer b/c of motor problems. I had problems last year with my 2001 150 Merc. Optimax 150 loosing power. I put alot of money in it changing fuel pumps, air intake modules and other things and it still never ran right. I took it to another mechanic after the motor quit running all together and 5 of 6 cylinders had water in them and he said it would cost more to repair than buying a good used motor. I was happy he was at least honest with me and he is a certified mercury dealer so I believe he knew what he was talking about and I saw all the spark plugs and they were solid rust.

My question is does anyone know anywhere that sells quality used motors. I want a 150 hp preferably in a Mercury so I dont have to change all my controlls out. Im not looking to spend a fortune something in the 2001-2006 model range. It goes on a 2001 20 foot fish master.