Marine engines and salt water corrosion

Pictured is a head cover off a 20 year old  Johnson outboard engine. This piece has significant corrosion and is something of an experiment.

The first view is the underside which has has salt water running through it.  There is  some furry corrosion left and some dark patches. 

To start with the furry white corrosion is fairly easy to blast off. More telling is the dark patches, this is is serious salt corrosion. In places it is deep and I am told I could blow holes in it !  So this piece  is really past it. However a 10 minute blast can get us to the point of being able to see into the internal water galleries rather than making a guess.

 

The right side has had more work than the left. In the top right the black area is deep

The right side has had more work than the left. In the top right the black area is deep

The outside had paint on it is various states of repair. Even here corrosion has got in, some areas have considerable pitting while others have some up to a nice finish.

The outside had paint on it is various states of repair. Even here corrosion has got in, some areas have considerable pitting while others have some up to a nice finish.

where we started from

where we started from

Where we ended up. The paint  has gone, some areas have come up nicely with a couple of vapour  blasts  while others are  just plain pitted and corroded.

Where we ended up. The paint  has gone, some areas have come up nicely with a couple of vapour  blasts  while others are  just plain pitted and corroded.

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