CORROSION on Bottom Plate

[truthbetold]

I just bought a 2004 Sportster 4-tech from a Seadoo dealer in my area. I took it for a test ride on the nearby lake beforehand and it rode beautifully. The boat looks pristine all around except for the bottom plate and around the outside jet area (not sure of the term). There is a lot of corrosion showing there. I mentioned it to the service manager who I dealt with before and has always been very honest. I told him it looked like salt residue. His answer was that the boat was never in salt water and it was pretty normal even in fresh water. He also said he has seen much worse on other boats and I shouldn't be concerned with it. When I got the boat home I scrubbed off a lot of the excess corrosion with a scrub brush and assorted household cleaners, but it didn't clean it as well as I would like.
Does anybody know what that bottom plate and the jet exhaust is made of ? Is it aluminum or steel ? Is there anything sold to clean the corrosion off the plate and the entire rear jet area that works really well ? Thanks for any help!

 

[Dr Honda]

Since you are in NY... I would have a hard time believing it has never been in salt water, and it is not normal. (it is common, but not normal) To me, it's a sign of neglect. Also... aluminum doesn't corrode in clean fresh water. It takes an electrolysis proses to get corrosion. That means dissolved minerals. (either salt water, or a lake with a mine drainage problem) If the last owner was washing it down after each use... it would not have started to corrode. But regadrless... a little crusty white corrosion isn't death to the boat.

All of the parts you are talking about are aluminum.

If you are only using it in fresh water... don't worry about it. clean it, and spray it down with some silicone oil. if you are going to use it in salt... I wold remove the parts, and give them a proper paint job to seal them from the salt water. Also... make sure your anodes are clean and tight. it will minimize the aluminum corrosion.

 

[truthbetold]

Thank you for the response, Dr. Honda. Although I show in my profile that I live in NY, this boat was bought in a Pennsylvania dealership where there is no salt water anywhere in the region. I have a vacation home in Pa. and thats where the boat will stay. I actually think that the boat sat in a lake for the entire boating season every year since new and was not washed down when taken out at the end of those seasons. There are a lot of boats up here that do that. I will be taking the boat out of water after each and every use, so there will be very little additional corrosion in the future. I'm sure glad it won't be a major problem. I was wondering if you ever heard of "Zepalum". I was told it will clean aluminum like new in just a few minutes (must have some kind of acid in it). I am trying to find a place that sells it, unless you've tried it and are not happy with the results. Also, where might I find those "anodes" you mention? I want to clean or change them if necessary. Thanks for all your help. I can see you have been a great help to many seadoo owners and I'm sure, like myself, it is greatly appreciated!!!!!!!!!

 

[DonoBBD]

There should be two aluminum half of a ball parts bolted to the rear part of the boat. On mine it is on the left side on the main bottom plate. The aluminum is facing up and bolted through.

This part is for electrolysis. These aluminum parts are bare and are there to collect all the corrosion ahead of the other parts. Make sure there are some of these on the rear of the boat. If not add some. The electrolysis aluminum should never be painted. Think of it as bait for fishing but for corrosion.

Cheers Don.

 

[timhood]

Just to clarify, the anodes are made of zinc. They shouldn't be painted, as they are designed to be "sacrificial", meaning, that they deteriorate to preserve the other metal parts that are in contact with water. Your boat will have probably two or three of these, and if they are heavily deteriorated, you should replace them.

You can, however, paint the ride plate as Dr. Honda suggested.

 

[truthbetold]

Checked the bottom of the boat and all around the bottom plate.. No zinc or aluminum anodes, as you call it. Does Seadoo put them on when the boat it built or are these add ons by the owner. In any case, I can't find any. This boat will only be in fresh water and never staying in the water overnight. Is there still a need to add these zinc anodes.

 

[timhood]

The anodes are pretty small and probably a medium-dark grey. Not something easily noticed if you aren't certain what you are looking for. They are rounded and only about 2" in diameter (not perfectly round, though). I'll try to grab a picture and post it.

Unless you are boating in crystal pure filtered bottled water you will want them. Salt water is much more aggressive than fresh water, but you'll want them nonetheless. If it's true you don't have them or yours are spent, they cost less than $10 each to buy.

 

[truthbetold]

Thanks, a pic of the anodes would be really helpful. Also, I just finished cleaning all the corrosion off the bottom plate. It is now bare aluminum. Should I paint it or just coat it with silicone, like Dr. Honda mentioned. I don't even know if it was painted from the factory when it was new. I never looked under a new boat.