Outdrive pressure tester is the tits. Or make your own from a decent radiator pressure tester.Shouldnt need more than 20-30 psi or so to find even hairline cracks when submerged. Exeeding that just makes it harder to keep system capped . Can also run one piece of hose and "t" for your pump tying inlet and outlet for dry joint apps

I have one of these little doohickeys I picked up at Menards. It has a schrader valve, gauge, and 3/4 NPT female on end. I used it to psi test intercoolers. Simply made up the appropriate fitting to reduce to 1/2 NPT, piped it to the intercooler inlet, and blocked the others off. Pressurized it with air at 30psi. I left intercooler on bench, came back an hour later, and still was at 30 psi on the gauge. Pretty neat little gizmo for 10 bucks. They come in 0-30psi, 0-60, and 0-100psi gauge range.

http://www.menards.com/main/p-144444...35488999278280

Very nice MT. Thank you!

here is what i am talking about for many in the industry who works on boats everyday. And I am showing dealer cost and retail. Not a huge mark up like I said in a past post.

http://www.stevensinstrument.com/gearcase.htm

Actually I have all 3 products in this link plus other Stevens products. I tried to sell the gear case pressure tester to members up here but no bits. If you work on boats and or your own app I highly recommend these 3 products especially the gear case pressure tester.

So many uses

1. pressure test exhaust systems, including headers
2. pressure test outdrives - any of them for seal leaks and or cracks
3. Pressure test oil coolers
4. pressure test pwr steering coolers
5 pressure test heat exchangers

their products are made for heavy duty usage daily not some cheap china junk.

Here is the deal - you can test the headers still installed to the engine - everything still installed in the boat. Just drain the headers first and then block off the needed ports - adapt the pressure tester - pump air and watch gauge.IMO apply heat to the header with a hair dryer for a bit - is the air still holding ? Come back an hour later - does it still have the same air pressure ? No leaks go boating.