Ok so I'm a newby when it comes to boats. I'm building a 1/12 scale model of a 22 meter fast pilot boat. I have one engine I might use but I am unsure how it gets its water for cooling. I work for the comapany that builds boat I am building a model of and know how the full scale engines get thier water for cooling. The engine I have has no pump or any thing on it, its an os .65. So let me ask this do I need a pump for water intake or is it supposed to be force fed through the hull intake?

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aakaak,
It can be done either way. If you think there will be any amount of slow speed, or idling around, it would be a smart idea to use a pump (that way you're not dependant on speed for water flow). If you really wanna get fancy, set it up with a thermostat to control cooling.
- 'Doc

Ok next dumb question. Who, what and where do I get these pumps. I will be doing alot of idleing around and just playing about. This will be a twin jet drive boat and because of limited space that is the reason I am going use the OS .65 marine engines, just gotta find one more now seeing as how they are out of production and all. Actually the jets cost more than the engines. I am getting them from an outfit in Astrailia and they are really nice, better than any thing I have seen on the market so far.

aakaak,
I don't have any idea of the amount of water flow you will need, so this suggestion may not work. So, how about a windshield washer pump? Uses 12 vdc for power, fairly compact depending on the particular one you use, not a huge amount of water flow but more than a little bit (hows that for accuracy?), and doesn't cost an arm and a leg (swipe it off the wife's car).
Or you might use a mechanical pump, small ones advertised for use with a hand drill? Some other centrifugal pump, they're a simple design (notice I said simple, not easy to make). A small impeller on the drive shaft, drive shaft fed through the housing? There again, it depends on how much 'room' you have in the boat. The electrical pump can be put almost anywhere, the mechanical one can't.
- 'Doc

PS - The windshield washer pump makes for a good pump for a fire monitor too. Out of a 1/32" nozzle I get about 6 - 10 feet of water stream. A 'self-priming' pump is easier to use than one you have to prime.