View Full Version : Taking on water

07-25-2005, 10:48 PM
If you have seen the bilge thread then you will empathize with this.
Almost from the day I got this 99 Mobius with 33 hours on it the boat has taken on more water than I would think normal.

I know about the gland nut on the shaft and supposedly by boat guy took care of that this last fall. But things have not really improved.

If I let the boat sit for two hours without the bilge connected I bet I would have enough water in the boat to see it comming out above the floor around the back seat. In 10 hours I bet it would sink.

When we sit with motor off in the water I am constantly hearing air comming (burppping) out of the exhaust pipes. Is this normal? I can apply pressure to the exterior flaps and stop the burping, but as soon as I let go they start again.

If this were a problem, wouldn't it mean that the exhaust has a leak somewhere? Otherwise the exhaaust is a closed system I would think. Water would either end up in the engine or ???

Any ideas on this would be appreciated.

Interestingly - my blower quit working this spring also and I have not been able to locat this yet. Maybe it has been submerged one too many times?


07-26-2005, 12:17 AM
Even if the exhaust flaps aren't working, you wouldn't get water into the engine from them. Where the exhaust curves up to the exhaust manifolds it is way above the waterline. If you think this could be part of your problem, pull the floor up and check your mufflers. If the boat was poorly winterized or for whatever other reason, maybe you have a cracked muffler or exhaust hose that has partially become disconnected. If this is the case, I could see where you could get a lot of water in the hull draining in through the exhaust.

If that's not it, leave the floor out of the boat and put it in the water. Maybe you'll be able to see where excess water is coming in from.

07-26-2005, 08:20 AM
You might have a cracked muffler. On my 2001 Mobius they were fiberglass mufflers.

07-26-2005, 07:04 PM
Cracked muffler or associated hoses.
Needs gland nut adusted, without new packing.
Needs new packing inside gland nut.
Bad bushing around rudder stem.
Leaking fitting / hose between water pick-up and motor.
Leaking/cross threaded bilge drain plug.

Dave, take the motor cover and floor off at the dock.

Get a flashlight and look for leaks.

Let us know.

07-31-2005, 12:49 PM
OK - so my boat guy lied. He said he repacked the nut when he winterized. I pulled the clamshell and the floor and sure enough water is coming throught the packing nut at a pretty good stream. Maybe after 10 hours it needs to be adjusted again?

Those are huge nuts. Anyone know what size wrench fits on them?
Do you loosen the lower nut so you can tighten the big nut and then run the lower one back up?

Thanks to all for support on this.

07-31-2005, 11:08 PM
Yes, that's how it works.

It needs to be done in the water. I take hatch cover and floor out. Simple.

Snug them, and check for a little drip ( necessary ).

Not sure of size, look like well over 1.5 inches... I use a pair of pipe wrenches or one + a large adustable. Just about too wide, as they hit each other. Be better to have a pair of wrenches the right size on-board.

Do not mar the soft shaft when messing with them.

Especially if you repack, picking out the packing has to be done carefully so you don't mar that area.

07-31-2005, 11:47 PM
Packing is done on the trailer, fine adjustment is done in the water.

If you can feel cushy resistance when winding the nuts together, then, the packing may be ok and the snugging adjustment is all that is needed.

08-01-2005, 06:10 PM
Well we will give it a shot and see how it goes.
Thx for input

08-11-2005, 05:53 PM
OK - so I tighened the nuts so that they leak about twice per second. Now I get a very unnerving vibration when I take off and things sound a bit louder.
I am wondering if I have a bent strut or shaft alignment problem.
If so - how can I tell and how big of a deal is it?


PS. When it rains it pours. I recently fried my hard drive, so while I was getting the new one all up to speed, I fried the video card. Now the A: drive is not recognizing disks and some new VPN software we tried to load killed my internet connection sharing on my LAN.

Anyone familiar with ICS and home LAN - maybe we can talk.

08-11-2005, 09:02 PM

1. How did you resolve the bilge pump?

2. I wouldn't run it. Sounds like you need to repack. It's not really hard, but a little time consuming to remove the old packing ( if you do that / could be done without !) and to wrangle and work the new packing into the nut. If you do so, you might slide the nut up the shaft towards the transmission and tape the exposed shaft with masking tape. Then, as you pick-out the old packing with various tools like fine needle nose or dental picks, or when work-in the new packing, you won't scar the shaft. For working the packing in, I like to use a thin brass drift that is softer than the shaft.

Dave, I'm a plugger backyard mechanic from a long line of the same. I own force-multiplying equipment, like hydraulic cylinders and winches and serious power tools, so the trouble can get worse quickly. Especially three coors into the job.

If its an hour to the dealer, and an hour back, you might handle it that way. Otherwise, go for it and all of us on here will help you solve it. Or give advice on how to raise it from the bottom of the lake, should need be.

08-15-2005, 11:18 PM
Deceptively easy -
Turns out my nice new *1 yr old) $400 ACME prop has a nice bend in one of the tips. I think we hit the boat lift with it if you can believe that. Put the old OJ 4 blade back on and the vibration went away. The packing nut leakage is manageable.

If you can believe it - we got the worst water in the boat last Sunday and Tuesday in the driveway (without the cover on ). It poured and with the bilge disconnected, well --- you get the picture.

Fortunately I was able to get to the drain plug before it got too serious..

I will deal with the bilge at end of season. Now that I can be on the lake without worrying abouot sinking I can just manually drain it on the lift.

Thanks for all your support.

Don't even get me started on the new brake job for my tow vehicle....


Shoemaker Mobius
08-27-2005, 10:06 AM
I'm curious why you don't remove the drain plug whenever you trailer your boat? Our dealer told us that when we pull the boat from the water we should always remove the drain plug so any residual water can easily drain. As we tow the boat on the trailer, there usually is a small amount of water that drains - apparently this is water that is below the level the bilge pump handles. The dealer indicated you want the boat to be able to be as dry as possible when out of the water - tends to help prevent mildew, rust, etc. Is there some reason why you leave the drain plug in?

08-30-2005, 09:21 PM
This is a good point. With the old outboard we used to always do that as well, from the outside. But with the Mobius it seemed that the plug was not intended for regular removal - I guess I thought I needed thread sealant every time. Well I have learned better since then and do pull the plug every time.

It would be nice if there was a little pocket or something righ on the dash to put the plug so you remember that it is out when putting in the boat.

Thanks to all for feedback. I have things under control. I do wish I did not have to remove the motor cover and pull the floor panel to tighten the jam nut, but not a big deal.

Still need to get the bilge wired correctly, but think I will have maintenance guy do that during winterization.


PS. Check out the new photo of the Mobius at the lake: