Bilge Water, Where's it come from?

[gene8084]

This may seem like a silly question, but where does the water in the bilge come from, and how much it too much?

I've only had my boat in the water for a couple hours since buying it and since that time I've been tuning and tweaking to get it ready. We had some trouble the first day out and by the time we pulled it out of the water the battery was dead. The bilge pump had probably been on & off while we spent sometime tinkering with the carb, listening to this and that as we tried to get the engine to run.

The point it there was some water in the bilge by the time we pulled it out of the water and pulled the hull drain plug. I'm talking inches, not a foot or anything, but while focused on engine fundamentals and replacing the sea water pump the past month or so I never stopped to think about whether there's anything else to maintain/replace in terms of gaskets etc on the transom/mount.

1. The hull is in great shape, a few minor scratches.
2. Powered by a Mercruiser 888 I/O.
3. I don't get any water in the bilge running on the muffs.
4. It's got a Merc I Outdrive, but looking at the absence of a preload pin on the drive shaft that the lower unit was replaced with an Alpha I.

Where & how's that water get in?
In relative terms, how much is normal / expected?
What should I be looking for, or replacing, caulking, or sealing?

Just thinking ahead...
Thanks...

 

[tashasdaddy]

Re: Bilge Water, Where's it come from?

what condition are the bellows in between the transom and outdrive. #1 place for a leak,,,,,,,,,,. also another overlooked place is the joint between the hull and cap . under the rub rail. when getting out of the hole, and coming off plane water splashes up under the rub rail and can come thru the joint. if you were just sitting, check any thru hull fittings.

 

[thrasher]

Re: Bilge Water, Where's it come from?

If you don't have water in the bilge when running on muffs, then it must be entering through a hole thats probably below the water line when the boat is in water. The usual places are:-

Split in the drive shaft bellows
split in the shift cable bellows
leak in the exhaust Y piece
Any accesories that have been mounted to the hull of the boat (not correctly sealed)
hole in the engine cooling system
split in the hull

You have ruled out the last 2 (by using muffs and you said the hull was good), so you need to check the first 4. Unfortunately you really need the boat in the water to check them..

Gary

 

[gene8084]

Re: Bilge Water, Where's it come from?

ok, I understand.

I'll inspect the bellows. As for the exhaust Y piece I'll have to look that one up to see how to inspect it. Other than that, I guess I'll get it in the water and watch carefully.

Thanks for the tips.

 

[GeneH]

Re: Bilge Water, Where's it come from?

A dry boat the size of yours should not take on any water at rest on water. I have had 30 different boats in my life, fiberglass and aluminum and none ever took on any water unless someone climbed in dripping with a wet swimsuit or a wave splashed over the side. Normal is none.

 

[gene8084]

Re: Bilge Water, Where's it come from?

ok, that's the kind input I'm looking for.

Now I need to find the leak.

 

[Ezrider_92356]

Re: Bilge Water, Where's it come from?

i have had problems before where my drain plug will ocasionaly not seal all the way

 

[gene8084]

Re: Bilge Water, Where's it come from?

i have had problems before where my drain plug will ocasionaly not seal all the way

I really hope it's that simple. It seems the only thing I can do at this point it get it in the water and observe. It's getting pretty cold here in CT so I'm running out of weekends.

It would be nice to id the problem and use the winter to get it squared away.

 

[thrasher]

Re: Bilge Water, Where's it come from?

Some people have suggested partly filling the hull with water and then look on the outside for a leak! Obviously you don't want to fill the boat up with water, just a couple of inches. It will help you find a hole if its in the very bottom of the boat, otherwise you just have to sit on the cold water and search..
In my experience, most leaks come from the back of the boat as that is where most of the holes are (drain, outdrive, trim tabs, etc) so start by looking at that end first..

Gary

 

[studlymandingo]

Re: Bilge Water, Where's it come from?

Gene,

The bellows as everyone suggested is the most likely culprit; the replacement is really a maintenance item, the first boat I ever owned had the 888 and I ended up replacing the bellows about every third season. Trust me, if they are leaking a little now, you're gonna have a gusher sometime next season.​

 

[Nandy]

Re: Bilge Water, Where's it come from?

The fact that your battery died is a reason to be very concerned. Fix that trouble before doing any serious boating or you might find yourself alone in the water with a dead battery and a boat taking water.
Good luck!

 

[gene8084]

Re: Bilge Water, Where's it come from?

The fact that your battery died is a reason to be very concerned. Fix that trouble before doing any serious boating or you might find yourself alone in the water with a dead battery and a boat taking water.
Good luck!

Thanks. Got that one. The turn key boat I bought had a fried starter and an useless alternator. Thus, my battery problems.

 

[gene8084]

Re: Bilge Water, Where's it come from?

Gene,​

The bellows as everyone suggested is the most likely culprit; the replacement is really a maintenance item, the first boat I ever owned had the 888 and I ended up replacing the bellows about every third season. Trust me, if they are leaking a little now, you're gonna have a gusher sometime next season.​

Makes sense. So I guess I must be prepared to pull the outdrive. It seems difficult to do a sufficient inspection of the bellows without removing it. It's ease enough to poke around, but I can't detect anything obvious.