Water in Bilge: How much is normal?

thomsonr

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Aug 1, 2010
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I bought a 17' bowrider with 3.7 Merc i/o this spring to get started in boating. It is an 89 that was keep in storage for some time after it's owner died.

Recently the boat sat at the marina for a week with the cover on while I was on vacation. After returning I had to run the bilge pump for several minutes to clear out the bilge. (I had cleared it before leaving). After returning I took the cover off for a day clearing the bilge before leaving it for a day with the cover off. I don't think we had any rain (but spot thunder showers were possible) and there was indeed some water to be cleared out.

Our local mechanic is trying to sell me on seal replacement, all the guys in the marina told me it was nothing to worry about as the plug might be leaking, etc. One suggestion was check for leaks with a flashlight both with the motor turned on and off.

What do you think? Thanks!

The New Guy
 

libellav15

Petty Officer 2nd Class
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Jul 3, 2010
Messages
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Re: Water in Bilge: How much is normal?

can you get it out onto a trailer or dry dock

if you can - get it level and then add water to the bilge with a hose

get it to just the above the 'unladen' waterline - the level in the water that the boat was sitting at when left unnattended at the marina

then go around the outside of the boat looking for leaks - if its going in its going to come out :)

check around seals, the plug, any fixings - speedo pick up etc and bellows etc etc.


good luck

adam
 

ph98223

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Jul 20, 2005
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Re: Water in Bilge: How much is normal?

i had the same issue with my 1994 searay 4.3 alpha one i started to look around and found that the shift bellows was torn so i replaced the main bellows and the shift bellows and it has fixed the problem you might want to take a look at those.
 

thomsonr

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Re: Water in Bilge: How much is normal?

ph98223: How much water did you have coming in and what was the cost to repair (if you don't mind saying).
 

Mr. Ross

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May 18, 2006
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Re: Water in Bilge: How much is normal?

With full mooring cover on, it is leaking somewhere if you found water. If a smaller tonneau cover that leaves fixtures exposed, it could be that if it rained, although I doubt it was rain water since you say the pump ran for several minutes.

Before too long you need to find that leak. I would have an auto bilge pump switch on there soon too.
 

H20Rat

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Mar 8, 2009
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Re: Water in Bilge: How much is normal?

get it to just the above the 'unladen' waterline - the level in the water that the boat was sitting at when left unnattended at the marina

That's a really good way to ruin a starter on an inboard engine. They are usually mounted to the bottom of the engine, and BELOW what is normally the water line.

only do that with an outboard!
 

ph98223

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Re: Water in Bilge: How much is normal?

i really never measured it but after it sat in the water overnight probably about 3-6 inchs up to the oil pan and it i think it cost about $100-150 with all the parts i did the work myself
 

hungupthespikes

Master Chief Petty Officer
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Sep 25, 2009
Messages
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Re: Water in Bilge: How much is normal?

Do you lift the outdrive when docked (trailer position)? This tends to extend the bellows and opens up any leaks from them. Will cost you a gimble bearing in a very short time.
 

Chris1956

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Mar 25, 2004
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Re: Water in Bilge: How much is normal?

I/O engines have several places that will spawn leaks, if maintenance is neglected. Using the "fill the boat on the trailer trick" to find the leaks is unworkable, since you will need to fill the boat to the top of the driveshaft bellows and shift bellow, and allow water to fill the U-Joints area and shift cable. This is very bad for those components.

A much better way is to tllt up the outdrive and inspect the two bellows for cracks and tears. If you see either, it is time to replace all the bellows.
 

scipper77

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Sep 30, 2008
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Re: Water in Bilge: How much is normal?

No water in the bilge is normal. If it rains and your mooring cover does not wrap around the bow you will get some water.

Any leak will ruin the boat in time. from wet rotted transom to damaged gimbal or starter etc... If you keep the boat in a slip and you want the boat to last it's worth the investment to fix the leak before there are more serious issues.
 

Chris1956

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Re: Water in Bilge: How much is normal?

Hey Scipper, how many boats have you kept in the water that had a dry bilge? The only one I have had that had a dry bilge had the kind of auto bilge pump that checks for water every 3 minutes. That kept it pretty dry. Every float switch model left some residual water.

Water in the bilge doesn't impact the hull much. They are made for it. It can rust I/O and inboard engine components, especially if it is salty.
 

scipper77

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Re: Water in Bilge: How much is normal?

Agreed that water will get into the bilge. I am saying that if it is coming through the hull it is a very bad thing. I have kept my boat in a slip only a few times for a week or so when on vacation and I can honestly say that I only got water in the bilge from rain getting under the mooring cover. If there is a leak somewhere then it should be addressed.

I apologize for stating so strongly that no water should enter the bilge. What I mean is that there is no acceptable level of leak. Obviously boats are going to get wet.
 

Chris1956

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27,030
Re: Water in Bilge: How much is normal?

I agree that there is no acceptable form of leak. Some Water will usually stay in a moored boat, due to washdown and the lack of the ability for the pump to get it all out.

Actually, a little water can be an advantage. I mounted my FF transducer in the bilge. I needed a cup of water in the bilge upon spring launch to get it wet. After that the residual water kept it wet and working.
 

thomsonr

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Re: Water in Bilge: How much is normal?

Well Gents as a follow up I left the cover off the boat for three straight days when we had no rain. Each day I went back and checked....no water when I turned on the bilge. On the second day of the check I had the boat out for 5 hrs.

Guessing my cover (a strange one indeed and real pain in the *** to put on) must be letting water in?
 

scipper77

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Re: Water in Bilge: How much is normal?

My bow cover snaps on to the horizantal surface around the bow. Water just runs right under the thing. I guess this is fairly common. It's also why I tarp my boat when not in use (the joys of trailering).
 

Bliner175

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May 23, 2010
Messages
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Re: Water in Bilge: How much is normal?

Unless its a full mooring cover, you'll get plenty of water.

I had the same experience with a new boat this year. Wasn't happy to find out that I have to buy another cover to keep the water out.

In the mean time, make sure you have a float switch installed for your bilge!!!
 
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