***Rusty Johnson***

[Ryboflavn]

I am having a rust issue with a 1997 Johnson 112. The engine only has 320 hours on it and my second (first rusted out) tilt and trim motor is starting to rust around the top of the piston. I feel that there is a breakdown on my rust defense but the anodes look to be degrading with time. The zinc marine grade spark plugs that are a little less than a year old are starting to rust along with the steering control arm and engine block bolts. I have three anodes on the engine two below the jack plate and one on the lower unit. Is there anyway to tell if I have a saltwater electrolysis issue and how can I correct it? The engine and boat are always pulled out on a trailer and washed and flushed right away. I also spray down the engine block with WD-40.

 

[Boatist]

Re: ***Rusty Johnson***

Welcome to the board.

You should probably repost over in the Johnson Evinrude fourm but maybe they will move it over there.

The zincs are more to protect the aluminum and I do not belive help much with the rust. Saltwarter is hard on a lot of the motor. My 1975 motor also has quite a bit of rust in some places. I think WD40 or Silicone spray help a lot with rust. Also check the Seals and latch to make sure it sealed up tight keeping as much Saltwater out at possible.

Hard to spray paint with zinc rich primers and paint after sprayed with WD40.
Also hard to repaint it and make it look nice with out a big tear down.

 

[5150abf]

Re: ***Rusty Johnson***

I found this stuff at Autozone called rust converter and it works really good.
Don't know how it works but it turns the rust black and stops it from growing.
Fixxed a small spot on a car I had,lasted for 2-3 years,still there when i sold it.

 

[ezeke]

Re: ***Rusty Johnson***

The anodes are there to protect all metals above zinc in the chain, including your bolts, stainless prop, etc. Once they are white with surface oxide (Zinc Hydroxide) they are no longer functional, so they need to be stripped occasionally and the anchoring bolts need to be cleaned as well. You can get and idea of how well they are working by applying an ohmmeter to the motor and the anode.

Using non-metallic surface coating on your gearcase will help to cut down the amount of aluminum that is directly exposed to the water.

Disconnecting your battery when not in use may help as well.

BTW, Salt-Away is a good product for washing the salt off the motor, inside and out.

 

[nightstalker]

Re: ***Rusty Johnson***

I spray my engine every year with a can of corrosion fighter that they sell at Boater's World, West Marine, etc. It leaves a brown dry residue all over the engine head but stops all corrosion. I've been using it for years on all three of my outboards and have never had a problem with rust or corrosion.
Nightstalker

 

[jameskb2]

Re: ***Rusty Johnson***

I found this stuff at Autozone called rust converter and it works really good.
Don't know how it works but it turns the rust black and stops it from growing.
Fixxed a small spot on a car I had,lasted for 2-3 years,still there when i sold it.

It's also sold as Naval Jelly. It creates a chemical reaction with the rust, (iron oxide) and stops it's spread. It's a good product to arrest rust and after a sanding and perhaps knocking off large flakes, you can use the product to stop further corrosion. Also, after use, you can prime and paint over it.

 

[Ryboflavn]

Re: ***Rusty Johnson***

Thanks very much for your replies I will give some of the after market products a shot. I have a rust converter that I used before I laid down a coat of zinc based primer and OMC White paint, but the rust seemed to come right back. As you probably could tell from the Admiral's reply, my anodes are white and pitted. What is the best way to strip them down (wire brush?) or just have them replaced? Also I made sure when I bought the boat that the latches locked down the cap tight; so I am not sure why the spark plugs rusted in less than a year. If you have any more ideas I am all ears and I will get to work on your suggestions. Gracias.

 

[ezeke]

Re: ***Rusty Johnson***

I use Mar-Hyde self-etching primer on aluminum and most marine steel. It is the best primer that I have ever used and you can just brush it on if you don't want to use a sprayer. One coat is usually sufficient before applying the base coat.

You can grind the anodes with a bench grinder, but as with any zinc product, be sure to wear a mask and work in a well ventilated area. If you should decide to replace, we have a company in Massachusetts that I can recommend with confidence. http://boatzincs.com/