The only thing I think I am going to use from the engines that originally came in my boat is the oil cooler lines. I want to clean them though. Any suggestions on how to or what to use to flush them out?

I would consider using something like Kerosene. Lacquer thinner and solvents like that may attack the rubber linings in the hoses.

it your taking the hoses out of the boat flush them in your solvent tank if not get some cheap 15 wt oil and run that thru them .

i flush them in my solvent tank and then blow them out with compressed air,if you had an engine failure,throw then in the trash and replace vthem.

gunk makes a product called " sc5" in a spray can. every napa has it and is avail in gallon cans as well. its a water solubable parts cleaner that works great. spray it down there and flush with a hose. then use a bucket with soap and water and flush. there is no reason to throw them away. if they are serviceable for your needs they are easily and completely cleaned and can be reused without worry. the trick is to use the water soluable cleaner first. that breaks up all the oil and everything that might be stuck to it and when flushed w/ water leave it " no film" dry. then warm soap and water cleans them absolutely virgin.

you can effectively clean oil coolers the same way altho wheni had to do those , i would use a pressure washer instead but after a bit of work, you get them perfect. since the oil goes thru the filter first anyway the vast majority of the trash is caught in the screens and in the filter . very little ends up in the cooler where it might be trapped and the lines trap none at all.

Don't hold your breath on the cooler catching it all. As mentioned, if metal went through it, it is money well spent to toss the cooler. Especially if your system is set-up with a bypass on the filter housing. I personally would'nt reuse but its what your comfortable with .

Brake Clean - lots of it and high pressure air. ...

solvent first, then flush with lots of hot soap water. Blow dry, then prep with a light oil and blow again. ready for use.

Thanks guys. I am getting started this evening. I have brand new oil coolers so they are clean although none of this stuff was from engines that were blown up. I just want to make sure everything is clean!

well. thats the right way to do it for sure.