Small amount of water in bilge - Maxum Boat Owners Club

dockhan · 06-11-2011, 12:57 AM

Hi Guys,
For the past 3 years, I haven't been able to solve a small problem. I seem to always have about a half an inch of water in the bilge under the engine. Its not enough for the bilge pump to pick up and doesn't increase if I leave the boat in the water at the dock overnight and also doesn't appear when I run the engine on muffs. When I bought the boat new, I noticed that the garboard drain plug was not seated well and had removed it and reseated it with 3M 4200 sealant so I know this isn't the source. All of the bellows look fine and I'm careful not to come off plane too suddenly to avoid backwash. It isn't rainwater either. One thing I noticed is that the bilge thru hull is pretty close to the waterline and there isn't a loop in the hose to prevent back flow from the thru hull. One possibility, I think, is that when backing off the trailer at launching, the bilge thru hull may dip below the waterline and take in some water that back flows via the hose into the bilge. I installed a one way check valve with thumbscrew hose clamps near the bilge pump thru hull so that I can remove the check valve periodically for cleaning but haven't been able to take the boat out yet to test it. I know it seems to be a small problem but I don't like water in my bilge.

seapuppy · 06-11-2011, 02:55 AM

well..that is one clean looking engine bay and pump....can't see any water.....if the thru hull is loose...then it needs to be resealed and reseated....if it's not rain/salt/engine....then it might be from a water tank if you have one....
the other thing to check is the butt plug..use a little of that teflon tape around the threads and see if that doesn't stop it...

SP

dockhan · 06-11-2011, 07:03 AM

Thanks,
Boat has never been in the Salt and I do use the teflon tape on the threads for the 'butt plug". The thru hull is also seated well and I don't have a freshwater tank. In 3 years I've been checking the engine thoroughly for any signs of a water leak but have found none.Thus I finally came up with the possibility that when launching the bilge pump thru hull might be dipping below the water line since the amount of water in the bilge seems constant. Anyway, thanks for your thoughts.

Capt Al · 06-12-2011, 02:38 AM

A small amount of water in your bilge is normal. Don't worry your pump will kick in if it rises otherwise it's fine. A half inch of water is nothing, I usually have more. From what I can see your bilge looks unusually clean...

TBarCYa · 06-13-2011, 02:42 PM

I'm going to say your guess about the bilge pump thru-hull is going to be fairly accurate UNLESS you do a bit of swimming/watersports from the boat at which point the water is most likely just from people getting back in while wet. I've noticed on heavy tubing days that the bilge will have a good deal of water just from the kids falling off the tube and climbing back aboard.

If your boat is like mine, the factory installed a manual bilge pump so you don't have a float switch. Before I installed the float, I'd hit the switch occasionally just to see if anything comes out.

ss3964spd · 06-13-2011, 02:58 PM

I get a small amount of water in the bilge from time to time but for the most part it stays remarkably dry.

Seems that you've eliminated darn near everything. If you suspect the water incursion to be happening by way of the bilge TH (or the garboard plug) it seems it should be easy enough to verify. Ensure the bilge is dry before launching, open engine cover, have someone in there watching as you back it in. If possible, have them sit on the same side as the bilge TH. Two bodies would be even better.

The garboard plug has "NPT" threads. In other words the plug is tapered. Installed and snugged up they don't leak. This you can also verify; install the plug, disconnect the bilge pump, and fill bilge with water high enough that the plug is submerged (but obviously not high enough to submerge critical components) then check for seepage.

Dan

capav8r · 06-13-2011, 10:42 PM

I had a similar problem that turned out to be a missing o ring on one of the blue plastic drain plugs on the engine. Who'd have thought that much water would leak from the missing o ring?!?! Bought new ones and viola, no more water in the bilge.

dockhan · 06-14-2011, 01:23 AM

I'll check on the "O " rings immediately. Were these on the top or bottom quick connects near the engine block?
Thanks for all of your ideas, Guys.

dockhan · 06-14-2011, 11:40 PM

Checked the 'O' rings, top and bottom, they are all there. I'll just have to wait until I take the boat out next time to see if the one way check valve on the bilge hose solves the problem. While the covers were off, I used the opportunity to replace the gauge lights with red LEDs from superbrightleds.com. I chose red to save on night vision and even though the needles on the gauges are red, I can still see them clearly. I used brighter LEDs for the 2 larger gauges.
I had earlier replaced the bicolor bow nav light as well as the anchor light with LEDs and all the trailer lights with LED fixtures since I do some night fishing.

ss3964spd · 06-15-2011, 02:29 PM

I'm so diggin the red LED's in the gauges............

TBarCYa · 06-15-2011, 04:15 PM

That's definitely sweet! I'm thinking that I may do the same but go with blue to match the rope lights that light the cockpit.