Mystery leak FOUND!

[SCORPIO]

For the last several years I've had a mystery intermittent water leak I've been unable to locate. Boat is an 89 300DA. It's overall a dry boat but I always have a little water in the bilge after a run. I can shop vac it dry and it never came back, until the next outing. I replaced all the bellows, hoses, seals, etc. It wasn't leaking from the steering pins or the fresh water system. I also noted that upon launching in the spring, I'd have that same amount of water in the bilge, even though the bilge was dry prior to launch. I assumed some wash water made it's way aft on the ramp. Well this past weekend I FINALLY located the source, the main bilge pump thru hull. We took some friends out and there was a light chop and periodically the bilge pump counter would register a pump cycle. I pulled hatches and couldn't see any water coming in but there was water in the bilge. We got to the place we intended to swim and I took a swim all around the boat. I checked the drives etc and as I was resting by the ladder I noticed that one of the pump thru hulls was not flush with the hull, you could have fit a dime in the space. I put my finger in it and was able to move it, it was that loose. It's never been loose in the 12 years I've owned the boat. I thought it was cracked but no, it's only loose. The chop and splash when running was lapping at that area and some water was getting in. Now that it was loose, it was allowing more water in. Also, when launching at a ramp, those thru hulls go below water line until the boat floats off the trailer bunks, allowing some water to enter.

BTW, Sea Ray installed those thru hulls with NO sealer under the flange or on the threads and nut. Since they are plastic, I'm going to replace them with Marlon as I've done in other parts of the boat. I put a little Lifecaulk around the outside of the flange to seal it until the season is over and I can pull the fitting. It's almost impossible to get to those thru hulls, I think I'm going to have to pull the manifold off that side of the engine as well as the trim pump so I can squeeze into that area, not something I want to do in the water this late in the season.

Anyway, It's gratifying to finally find that leak.

 

[bobeast]

Great find. How ironic is it that the bilge pump plumbing was responsible for the need for a bilge pump?

 

[Strecker25]

You may have just helped me find a mysterious leak.

our new 410 collects a little water in the bilge, always more when we’re at the boat. I assumed it’s a freshwater leak, and I even have a water dye additive coming tomorrow to test that theory, but I just remembered one of our discharge they hulls was noted as loose on the survey. I think it’s for a sump, so we might be readmitting the water that was just evacuated back into the boat.

so, thanks! And glad you found your culprit. Water is the bilge drives me nuts.

 

[MonacoMike]

I got a new leak to chase this weekend. Ugh! Glad you found yours b

 

[Bobfro]

I have SOLVED this issue, WATER IN BILGE, ONLY WHEN RUNNING!!!! for many years, my boat sits dry, then after taking the boat out, 3-4 gallons of water in the bilge.....WTF....., more people on the boat more water in the bilge, less people on the boat, less water. I've gone through every thread on this topic: no it's not the transducer, AC Seawater inlet, Engine coolant hose, Water pump, Fresh water flush kit, rain water in a compartment, fresh water holding tank, Hot Water Heater...NO NO NO, don't waste your time replacing those through transom fittings and hoses, sealing trim on the swim platform, or any other brain storm thought you may have....... So simple, yet so stupid.......Your bilge pump hose is the problem.....there is no check valve or discharge baffle on the rear engine bilge outlet discharge hose, the hose has a small loop about 2-3 inches above the discharge outlet. This loop was designed to stop backwash.....GUESS WHAT, the loop is too small... your method of fixing is your choice, however that's the problem.....the backwash pushes in through the bilge outlet, upward through the small 2in high loop, the into the bilge pump itself and fills the bilge itself........ how stupid / how simple could this be, and over thought so many times........PROBLEM SOLVED