Mystery Leak - malibu sunsetter

[torontoboater]

Hi all - I have a mystery leak in my 1999 Malibu sunsetter LXI. The dealer who manages the maintenance and repairs also cannot diagnose the problem. I have attached pictures. It is a very slow leak which appears at the back of the boat, and slowly spreads, on the carpet just to the port side of the HDS box cover. The dealer tested to see if there were any leaks by filling the bilge, and there were none. The bilge is generally empty. It doesn’t appear to be from the HDS box either which has virtually no water and the hds box seems dry (the compartment has only the usual very few drops from the shaft packing) so it doesn’t appear to be coming in from there.  It generally takes about 24 hours of sitting in the water before it appears, and then spreads very very slowly, and only on the port side carpet. Any thoughts from this group? 

[03RLXi]

You'll more likely find Malibu boat specific help at https://www.themalibucrew.com/index.php?/forums/ 

[Ronny61]

How long have you owned the boat? Did you have any service work done to it right before this problem started? If the carpet is dry, how long would it need to be in the water before it looks like the picture? If the boat was sitting in the water without the engine running would this still happen? Everything is a process of elimination so try some different scenarios that will eliminate things were water could come from.

[Ski_Dad]

have you greased the rudder lately?

[S1Pitts]

If you have the older air pressure AirGuide type speedos check for rotten rubber lines.

 

[VermontSkier]

Fellow Malibu owner here, though not a sunsutter but similar vintage. I too had a mystery leak which resulted in small amounts of water on the carpet towards the back of the boat. This spring when I pulled my boat from storage I checked the swim platform bolts and they were spinning freely, so I pulled the gas tank, cleaned the back area thoroughly, removed and cleaned the old caulk off the bolts and then reattached and tightened them with new marine grade sealant. I also removed the pitot tubes since the boat has Perfect Pass and the leak has been fixed. I have a sportster so there is no rear trunk hence why I pulled the gas tank. My friend with a response removed the floor of his ski locker and was able to access the bolts. Worth a look!

[APB]

platform bolts need to be resealed.

[torontoboater]

Thanks all - very helpful advice!  Much appreciated, as always!  As suggested, I also posted on the Malibu site if they have any additional thoughts. 

[VermontSkier]

Did you put a wrench on the swim platform bolts to see if they are tight?

[ImperfectPass]

Do you have a hot shower? If so and it’s leaking it will run out on the carpet in that spot.

[torontoboater]

Thanks everybody for the great advice.  It seems that one of the swim platform bolts is loose (on the same side as the leak), so maybe that is the culprit.  I will have this tightened in a few weeks and hopefully that will solve the problem for next year.

[VermontSkier]

@torontoboater I definitely recommend, if you have easy access, to re-caulk the bolt as well as tighten. Hopefully its a quick fix!

[torontoboater]

Thanks VermontSkier.  How do I access the bolt?

[VermontSkier]

@torontoboater you should be able to remove the base of the ski locker, it may be screwed down, and then there might be just enough room to get a wrench on the end. It will be a little tricky but my ski partner was able to do it on his response. I have a sportster, so I had to pull the back seat, gas tank, and all the hoses to get access. 

[torontoboater]

Thanks!

[torontoboater]

VermontSkier - what product should I use to recaulk the bolt, and should this be done on the inside and outside of the boat?

[VermontSkier]

So I removed all the bolts and the platform bracket- cleaned all the old caulk off the bracket, bolts, and hull. Used a heavy duty degreaser to thoroughly clean everything and a fine metal brush to get the old caulk completely out of the holes in the hull. Then I used loctite marine adhesive sealant- lots in the holes both inside and outside the hull and a nice bead on the platform bracket. You can find this at Home Depot or order it on amazon.

Since I had to do all the hard work of removing the gas tank and hoses, I wanted to do a good job that would last another 20 years. You might be able to get away with just tightening.

 

https://www.amazon.com/Loctite-Adhesive-Sealant-Cartridge-2016891/dp/B01DKIQ5Q6/ref=asc_df_B01DKIQ5Q6/?tag=hyprod-20&linkCode=df0&hvadid=191952284066&hvpos=&hvnetw=g&hvrand=17407207525152201849&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1027360&hvtargid=pla-310299137239&psc=1

[torontoboater]

Thanks!

[MitchellM]

The collective wisdom on this site never ceases to amaze me!

[VermontSkier]

I hope my experience was helpful! I should add that you will want a second set of hands to hold the bolt on the outside with a wrench while you tighten with a socket. This project seemed daunting since I had to remove so much from the boat but I am learning my boat inside and out and it’s cool to be able to keep these older boats in top shape!