Water in bilge on 270 SLX

paulswagelock

paulswagelock

Well-Known Member
Oct 25, 2010
2,204
pa
Boat Info
2018 SDX 270 OB 300 Verado
Engines
Verado 300
I have owned many boats, and maybe I was just lucky, all of them had bone dry bilges. To be fair, many of them had self bailing cockpits.
So I get that rainwater or dripping passengers will make its way to the bilge on my 270 SLX.
However, sometimes when we are out for the day and anchored, no rain, if I hit the switch for the rear bilge pump, it will pump out a gallon or 2 of water. Never enough to kick on automatically, but some. I have looked all over the bilge and can not find any leaks. Some days we can be out all day and it does not do it. I think it is related to how many people are hanging out on the back of the boat, and how hard the waves are coming at the back of the boat while anchored, but I do not have enough data points to say for certain. I had the drive pulled and serviced at the end of last season, and it still does it. I can not find any water trail / stains anywhere, near the ladder, exhaust, trim tabs, outdrive assembly, etc. It will sit in the water at the dock for a week or more and not pump anything when I hit the switch, so it appears to be either passenger of wave related, I think.

Any suggestions on where it might come from? I know one person whose garboard drain leaked where it was mounted on the boat, not the drain plug, but the plug holder. I can check that when pulled at the end of the season. Maybe my transom is not exactly straight and flush and it weeps in at the gimbal housing somehow??
 
I feel your frustration, Paul. Chasing leaks can sometimes be a very draining experience. Based on what you're saying, though, here's what I might try to see if I can locate it. First, make sure you have a good view of the entire inner transom assembly - either by contortionism or the use of a good snake camera or your phone on a stick, and also good lighting. Then, I'd go out and stern anchor the boat so as to try and mimic the conditions you are thinking cause the problem. If you bring a couple coolers, you can fill them with water and secure them to the platform to mimic extra weight, too.

Besides the inner transom area, I'd also be looking at the exhaust - follow it from the elbows to the inner transom plate and look at all connections. Do you have thru-hull exhaust? That would be another spot to look at.
 
I do have through hull, but don't see any water or stains on the inside.
The bilge is very clean with exception of the very deepest/lowest spot where this water collects, so it would be obvious if any water was running down to the bilge from these higher penetrations (with the exception of the transom area blocked by that way too big for the bilge 496 in the way).
Good idea to simulate the weight. As I said, sitting at the dock or driving does not seem to do it from what I can tell.
 
Another thing I've done in the past, is to use chalk. Draw chalk on areas where it's possible for water to come in. For example, on the bottom side of a bolt that penetrates the hull. If it leaks there, it will wash away the chalk. Another method is to tape paper towels in key areas. Even if water leaks on it, then dries, you'll still be able to tell.

Yeah, that's a big hunk 'o iron. Boat maintenance would be so much easier if there was no engine!

Take a good look at all of the exhaust connections. Your phone, on video (with light), attached to a stick (if need be) is a good tool.
 
I have 3 ideas for you that we have experienced:
1 Exhaust hose clamps are slightly loose and slowly leaking.
2 The shaft seals for the thru hull diverter "flaps" are bad and leaking. This is a slow leak and hard to diagnose.
3 I found the garboard drain plug fitting to be leaking from the inside of the boat at the bottom. I removed the screws loosened the fittings and sealed the it to the hull with silicone and replaced the screws. I also found that the bottom mounting screw was stripped, which had to have happened during the the manufacturing process, since I have never touched those screws until I found the leak. I replaced it with a slightly bigger diameter screw.

Finally, everything drains to the bilge. So if you have people swimming and getting back on the boat to dry off, it is impossible to keep the bilge dry. Aside from a couple coolers we never used, the cockpit of our 240 drained overboard, so we never had this issue. It took awhile to get used to it on the 270.
 
Check where the steering arm comes through the transom. You might have a leaky swivel shaft seal.
 
I had a similar problem with my 270 slx. When running the boat or pulling the kids on skis or tubes, the bilge would fill with water. Sitting still or docked at the marina, no water would get in the bilge. I discovered that the caulking around the rear of the boat under the swim platform was deteriorated and when the boat was getting on plane and the stern was in the water, water would enter where the caulk had "rotted" away. Removed old caulk and installed new and no more water! Hope you find your problem!
 
Could you be more specific on what / where you found the caulk deteriorating? Going from memory, I can't picture where any might be.
 
My old 300 SLX was the same way. Towards the end, I'd get a shop vac and make sure the bilge was bone dry, then at some point during the cruise, I'd open up the hatch and see a small amount of water down there.

It frustrated me the cockpit all drained into the bilge relying on the pumps to get every drop of water out.

I don't really have any answer to the problem, but I find it's comforting when I know others share the same boat issues as me. :)
 
Not the same boat... but on my 260 Sundeck. I had a floor drain aft near the step to the swim platform that drained over board...when I would come off plane quickly.. that drain would back flow into the cockpit and the lake water would work it's way into the bilge from the engine hatch lip drain. This would happen when coming off plane quick when tubing or skiing..

That same boat had storage under the forward floor and center floor. They were connected with tubing. The tubing was above the storage floor and each compartment would hold a fair bit of water at each bulk head from Anchor and ski's, floats etc. When you would get up on plane that water would work it's way back to the bilge.
 
Having the same issues on our 260 Sundeck
Boat have a wake tower, maybe a bolted-on arch ?
I've ordered new gaskets where the tower mounts to the hull on mine. They are in bad shape & I thought I sealed them with silicone to get through last year. I believe I'm still getting some rain water in that's making it's way to the bilge.
The swim platform mounting bolts on mine were resealed last Summer while the dealer had it.
 
dirvan said:
I had a similar problem with my 270 slx. When running the boat or pulling the kids on skis or tubes, the bilge would fill with water. Sitting still or docked at the marina, no water would get in the bilge. I discovered that the caulking around the rear of the boat under the swim platform was deteriorated and when the boat was getting on plane and the stern was in the water, water would enter where the caulk had "rotted" away. Removed old caulk and installed new and no more water! Hope you find your problem!
Click to expand...

Can you tell us what caulk? Where?
 
I could be wrong but I believe he is talking about the caulking along the bottom of the rub strip where the rub strip runs along the stern. When you are towing tubes or pulling skiiers or running fast and slow down the water rushes up towards the transom and sometimes runs up on top of the swim platform which means the rub strip is encountering a lot of water. The caulk line that seals the bottom of the rub strip is what I believe dirvan was talking about.
 
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Sounds like a leaking swivel shaft seal where the steering arm goes through the transom. Its a poor design as its a steel shaft that corrodes and kiils the seal as well as the housing if you are in salt water. It happened on my 240DA. Fine with one or 2 people. Loaded up I had a bilge full of water. The seal sits just above the waterline. When loaded its under water. If its that there are 2 choices. THe cut through method or pull the motor and make the repair if the housing is not corroded or just replace the entire transom assembly. $$
 
That is correct sibnai1, The caulk below the rub rail on our boat had deteriorated and was gone in several places. When pulling tubes, skiers, before the back of the boat came up on plane, the water would come in where the caulk was missing. Recaulked everything and have had no issues with water in the bilge
 
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