Outboard corrosion, no good?

SpearRib · 20 October 2013, 08:46

Ive got an outboard on offer cheapish, 2005 Johnson. Problem is its off a yacht and has a bit of corrosion under the paint around the leg and transom bracket.

Is this unfixable or expensive?

colcreate · 20 October 2013, 10:04

The corrosion you can see might be cosmetic and easily fixable, rub down prime and paint etc. Without pictures and more info who knows? 2 stroke or 4 stroke, model?
It might also be an indication though on the corrosion you can't see inside the engine or to the lack of general care and maintenance. On a yacht as an auxiliary it may have been used infrequently in salt water and never flushed out. Could be about to turn into dust on the inside or could be mint.....

SpearRib · 20 October 2013, 10:19

Thanks col, that was my concern. Might be hard to get pics. So far the only visible corosion is under paint, nothing major just bubbled paint, but who knows what is on the inside. Whats the easiest way to see what the inside is like, ie cooling system etc?

colcreate · 20 October 2013, 11:04

Model?
A bit of paint bubbling on the leg of an 8+year old motor is probably nothing to worry about and is easily sorted.
There again I have seen auctions for corroded spares & repairs outboards of the same age, must have had a hard life!
Without pulling bits off and looking inside for corrosion you can't say and if getting a photo is a problem I expect there is even less chance of getting the spanners out.
Usually easiest part to remove to examine internal waterways on a two stroke is the thermostat cover but general overview of how the motor looks, runs and pumps water will give you an idea if it's junk or not. Let it run to operating temp for a while and do all the usual checks on buying a 2nd hand outboard. Research the model on the net to see if there are any common issues.

SpearRib · 20 October 2013, 11:17

its a 8hp. ill ask to view it running and if i can remove the thermo cover for a looksy. mate of a mate so hopefully not too difficult.

spartacus · 20 October 2013, 12:18

Check the sacrificial anodes on the outboard. These are made of zinc so that electrolysis doesn't destroy the main body of the outboard. Relatively cheap to replace. If you remove the thermostat - remember to renew the gasket.

SpearRib · 20 October 2013, 21:21

maybe i wont remove the thermostat then hehe. the anode is actually good looking. strange. the corrosion is some surface bubbling at the round part of the leg where it meets the prop (the area that houses the seals etc)

9D280 · 21 October 2013, 17:51

You say its off a yacht. Chances are that end has been dipping it the water, and so any galvanic nonsense Will have been concentrated there.

On the flip side, the reason I no longer have a Yam on my transom is I went to change the 'stat and found the whole head had turned to shortbread through an 0.526" earth strap in the bowels of the tray snapping long long ago...

Check any anode sizes with new ones- you might be surprised!

spartacus · 21 October 2013, 19:55

Quote:

Originally Posted by 9D280

On the flip side, the reason I no longer have a Yam on my transom is I went to change the 'stat and found the whole head had turned to shortbread through an 0.526" earth strap in the bowels of the tray snapping long long ago...

Funny you should mention that... on my Twatsoo there was an earth wire near the lower leg to the mid leg that had broken its connection. Luckily I spotted it before it caused any damage.

9D280 · 22 October 2013, 17:40

Lucky. I now check the Merc regularly...

... And before you all think I measured the wire to one thou' accuracy- I'm putting that down to fat fingers on a small keypad!