Gray discoloration on outdrive?

[Donut147]

What makes the gray discoloration I see on many of the Mercruiser outdrives I see. It always mistifies me why a drive will be pristine looking on the lower part, but have that gray color on the upper part. Intuitively I would have expected the opposite, since the lower part is in the water. What's the deal?

Is there a way to clean that off?

While I'm asking, one of the decals on my upper unit is starting to peal off. Any suggestions on a good adhesive to repair that?

Thanks.

 

[Gary H NC]

Re: Gray discoloration on outdrive?

Probably the waterline stain is what you are seeing. It will clean off.
I use super purple cleaner and it works well.

Try some 3M decal and emblem adhesive from any auto parts stores.

 

[Silent Player]

Re: Gray discoloration on outdrive?

Is it chalky? If it is, this is caused by heat evaporating the water, and leaving a mineral deposit. Some out drives are more prone than others. The Bravo series, especially Bravo III are considered to run at high temperature. Cheap insurance is to get a drive shower. Not only will this cool the upper gears (increasing longevity), but will keep it clean as well.

The reason it it on the upper case only, is do to the fact that when at speed, the upper case is not submersed in the water. Thus, not getting cooled.

 

[Bondo]

Re: Gray discoloration on outdrive?

this is caused by heat evaporating the water, and leaving a mineral deposit.

Ayuh,.... Exactly...

 

[ziggy]

Re: Gray discoloration on outdrive?

yep. ^^^^ what they said.

+

and lime away takes it from looking like this...

to looking like this....

obviously two different times of taking pics of my drive. but i did nothing to the black finish other than lime away it while it was on the boat, then wash it off with boat soap and water...

 

[Donut147]

Re: Gray discoloration on outdrive?

Thanks! Looks like I need some 3M decal & emblem adhesive along with some Limeaway. Ziggy, your picturea are right on, mine isn't to that point, but that's what I'm asking about. I recently bought a new boat and this is going to make it look even more awesome.

Thanks for everyone's contribution on this!