Bilges full of oil... oh ****!

[DAKA]

I sincerely hope I am being pessimistic but your shaft which I assume is stainless steel shows significant rust which may indicate it nhas been submerged in stagnant salt bilge water which could mean your aluminium gearbox may have being acting as a sacrificial anode protecting the shaft / coupling while submerged in salt bilge water.

Having had a bayliner with a submerged aluminium tank that went porous I am concerned that the whole of your gearbox back could be porous after you replace the back seal.

Cover the whole gearbox with soap water , wrap a wet rag around the rear seal and pump you gearbox up to 5 bar pressure via the dipstick hole looking for pin holes.

 

[Firefly625]

I sincerely hope I am being pessimistic but your shaft which I assume is stainless steel shows significant rust ............

Daka, thanks for all you help and I do appreciate your pm's, have taken note of gearbox available.

I can assure you the shalft, which is not pictured is lovely clean stainless steel, the coupling is in steel and rusted to hell, see photo. Looks horrible, but still sound if it wasn't for the fact we want to now remove it. So bolts will be ground out and it will be removed. But if sound will be re-fitted, although will have a fresh coat of hammerite... or perhaps re-newed. I am boating on a budget, please don't make me spend any more..

 

[volvopaul]

I sincerely hope I am being pessimistic but your shaft which I assume is stainless steel shows significant rust which may indicate it nhas been submerged in stagnant salt bilge water which could mean your aluminium gearbox may have being acting as a sacrificial anode protecting the shaft / coupling while submerged in salt bilge water.

Having had a bayliner with a submerged aluminium tank that went porous I am concerned that the whole of your gearbox back could be porous after you replace the back seal.

Cover the whole gearbox with soap water , wrap a wet rag around the rear seal and pump you gearbox up to 5 bar pressure via the dipstick hole looking for pin holes.

If you pumped the casing up to that pressure you would blow the oil straight past the front and rear lipseals!

As long as the engine is bonded to the main anode I cant see the box being a large anode, from the pics I have it just looks like surface corrosion on the casing, bit powdery in effect.

 

[DAKA]

If you pumped the casing up to that pressure you would blow the oil straight past the front and rear lipseals!

As long as the engine is bonded to the main anode I cant see the box being a large anode, from the pics I have it just looks like surface corrosion on the casing, bit powdery in effect.

When I wrote it I had thought the whole thing had been submerged in bilge water, when Firefly pointed out the flange was steel and only the prop shaft stainless then I accept the gearbox should be intact, you know what you are doing.
As to the attempting to add panic in order to sell my spare

My spare gearbox is 2.5, firefly needs 2 so mine isnt any good, the second link I sent was a 2:1 which isnt mine, I wasnt trying to sell my spare gearbox, I keep all sorts of spares for my boats and being pessimistic happy to keep them unsold

In the unlikely event that you do find damage to the casing then send me a pm as I can direct you to a spare casing which was available for £300 , again no connection to me what so ever.