Tips on tracing a leak?

RichA · **Joined:** Wed Jun 25, 2014 12:37 pm **Posts:** 98

During a day (~7 hours) on the water, I notice my bilge pump running once or twice. It may run more when I don't see it. After loading the trailer, I usually get a good stream of water when I pull the plug. So, I've got a leak.

My mechanic says on this boat it pretty much has to be coming in from the back of the boat, around the outdrive penetrations. I have looked as much as I can in the engine compartment when the boat is in the water and I can't see any indication of where the water is getting in. No dirty streaks or unexplained wet areas. Of course, though, I can't see behind the engine. Mechanic says boots and bellows look good as far as he can see from the outside.

So, any tips on how to pin this down without pulling the drive?

I do have an inspection camera, and I should take that with me on the water to get a better look behind things.

LouC · **Posted:** Mon Aug 25, 2014 7:49 pm

Start with a totally dry bilge. Get some of that blue colored paper toweling. Roll up lengths of it and stuff it all around the inner transom mount. Back the boat in the water. The leak may show up on the toweling.

NiagaraChillin · **Posted:** Tue Aug 26, 2014 12:47 am

Basically, there is only a few places water may be coming from. Drive bellows, hull plug, exhaust fittings, transom seal, or hull compromise. I have had leaks in all of these, except a hole in the hull(!). The easiest to fix is the hull plug and exhaust fittings. For hull plug, just remove the 3 screws, clean the area, put a new one back on with plenty of sealant. For the exhaust fittings, usually it just takes tightening the large hose clamps.

The harder fixes are the bellows and transom seal. For bellows, yeah, ya gotta remove the drive. For transom seal, well......see my thread on that bit of fun here: http://www.smwebhead.com/phpBB3/viewtopic.php?f=2&t=13130

One indication that it may be transom seal, is if you don't see water trickling in while just sitting in water. While under way the drive is basically "pushing" against the stern to make you go forward, if your transom seal is loose/bad, this can cause the drive to "separate" from the stern and allow water in. That is what happened to me in the above thread.

Paul I. · **Posted:** Tue Aug 26, 2014 7:06 am

On a past boat, it was coming from the engine air vents when on plane.

Jake · **Joined:** Thu Jun 06, 2013 9:26 pm **Posts:** 7

I had a similar situation, it was the drain plug fitting not sealing to the hull. I took a garden hose and started filling the boat with water in the driveway, found the leak right away. You don't want to submerge any electrical doing this.
My previous boat took on water as well, this one was a bugger to find, it was the bow eye. When we were at rest or slow cruising, and there were enough people in the bow submerging the eye, water would leak in through the bolt holes.

RichA · **Joined:** Wed Jun 25, 2014 12:37 pm **Posts:** 98

NiagaraChillin wrote:

Basically, there is only a few places water may be coming from. Drive bellows, hull plug, exhaust fittings, transom seal, or hull compromise. I have had leaks in all of these, except a hole in the hull(!). The easiest to fix is the hull plug and exhaust fittings. For hull plug, just remove the 3 screws, clean the area, put a new one back on with plenty of sealant. For the exhaust fittings, usually it just takes tightening the large hose clamps.

The harder fixes are the bellows and transom seal. For bellows, yeah, ya gotta remove the drive. For transom seal, well......see my thread on that bit of fun here: http://www.smwebhead.com/phpBB3/viewtopic.php?f=2&t=13130

One indication that it may be transom seal, is if you don't see water trickling in while just sitting in water. While under way the drive is basically "pushing" against the stern to make you go forward, if your transom seal is loose/bad, this can cause the drive to "separate" from the stern and allow water in. That is what happened to me in the above thread.

All that matches with my understanding. But first I have to figure out which of those possibilities is the one (hopefully there is only one!)

Today, as it sits on the trailer, I'll plug the bilge, disconnect the pump, and fill it with water as much as I can without getting the electronics wet, and watch for wetness outside.

If that reveals nothing, I'll dry it out thoroughly, put it in towels like LouC suggested, and put it in the water, and let it sit for maybe an hour, checking the towels periodically. If that doesn't reveal anything, I'll close the hatch and take it for a short run at speed with the towels still in there, and check again.

The air vent area doesn't seem to get a lot of splash, but the thru-hull exhaust on the sides of the stern definitely get into the water from time to time. Maybe I should hose some water over them to see if any gets into the boat.

I've not found any indication of any water on any of the water lines or exhaust components in the engine bay (at least the ones I can reach).

Thanks for the tips!

SeaTea · **Joined:** Sun Aug 11, 2013 6:44 pm **Posts:** 13

Another way I have read is to dry everything and give everything a good coating of baby powder, The leak washes the powder away and you can trace it to the source. I haven't used this technique (yet!) but I've heard positive results.

Wouldn't hurt to try it and you can just rinse it off to clean up!

www.iFourWinns.com

Tips on tracing a leak?

Who is online