Re: Need some help with pontoon leak.
Generally each section of the boat has a baffle between them so you have , nose cone,baffle front section, baffle, rear section end cap, and the bungs in the top should be open underneath once you remove the plug.
Alot of leaks aren't below the water line, water splashes all over under the boat so the leak could easily be on top and air expands and contracts quite alot in the tube so apparently your hole isn't big enought to vent air freely, as the tubes cool from being run throught the water they will actually create a vacuum and suck water in the leak.
To find the leak you need to get some air pressure in the tubes and spray it down with soapy water, any dish soap will work, alot of cracks are at the very back of the rear brackets or the the very front of the front brackets, both are stress points and are known to fail there.
You don't want anymore than 5-6 psi in the tubes and the baffles may bang but that is just because you are applying pressure to one side and is normal.
Spray every weld you can find adn eventually you will find your leak but you will need a welder to fix it since the best way to get the water out is to drill the back of each section right by the keel.
Good luck and let us know how it goes or if you have anymore problems.