Mercruiser bravo 2 oil leak

Grubble said:
What outdrive do you have? That kit says Alpha One Gen II, your post says Bravo 2. The kit is the normal kit for doing the Alpha One Gen II impeller.
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My outlive is a Mercruiser Alpha One Gen II, Circa 010.

Many thanks.
 

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dave1dpc said:
Surely this is an ALPHA leg not BRAVO where the water pump is on the engine?
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Yes mine is a Alpha One Gen II.

I jumped on an existing thread as it was along the same lines as my problem. Incidentally, my engine also has its own separate water pump.
 
In 30 yrs of working with drives I have never had to replace an upper drive shaft seal on an Alpha drive, only when doing a complete rebuild. I would pressure test the lower half as I explained in an earlier post as I have replaced dozens of lower seals under the water pump.
 
spannerman said:
In 30 yrs of working with drives I have never had to replace an upper drive shaft seal on an Alpha drive, only when doing a complete rebuild. I would pressure test the lower half as I explained in an earlier post as I have replaced dozens of lower seals under the water pump.
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Sorry to keep coming back to this, but by "Lower Seal", do you mean this;
 

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Under the water pump impellor you have the metal base plate abd under that you will see the shaft going down into the gearbox with a usuallly yellow plastic round housing which has two seals, one on top if the other, this is where oil can leak out. You test it by pumping air at about 10 psi into the drain plug hole but you have to block the transfer passage to the right rear of the water pump base plate, there is a small orange O ring there, I put a wide flat washer over it and hold it down with a small G clamp or molegrips otherwise it won’t hold the pressure, then if holds the pressure all well and good, if it doesn’t then spray soapy water around the seals while turning the shaft, also around the shift shaft just in front or the prop shaft, any bubbles shows its leaking, I have had 90% of leaks on Alpha drives to be under the water pump. If its the water pump seal its easy to change, there is a small hole each side of the plastic housing, just get two pointed screwdrivers and lever it up, you can buy the housing complete with seals and the O ring and you just fill the space between the seals with waterproof grease and lube the O ring and press it in, the baseplate holds it in place when the pump is installed.
 
And then rebuild the water pump with a new seal kit and the all important little red o ring to seal the oil transfer pipe.

And that should be it?

Again, thank you.

Ribtecer
 
in 35 years I have replaced numerous drive shaft seals in the upper housing due to wear and tear from splitting the casings to service water pump,and from overheats
 
Ribtecer said:
Thank you so much for your advice and experience here Spannerman.

So I should replace this;

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I've had a hell of a job getting this thing out, the first conventional way of two screwdrivers ether side definitely was not going to work. All that achieved was skinned knuckles!!

I saw online people grinding them out, but I didn't like that way as all that dust would go down into the gearing.

I tried to melt away a channel with a soldering iron all the way up it, to allow me to pinch it together and lift it out - that didn't work either.
 
Last night whilst surveying my options with a glass of wine I came up with a new idea.

It worked a treat, it lifted out with ease and it was easy to clean up the mess left behind.

And it's very evident this was the cause of our leak.

New part arrives tomorrow 🤞

Very keen to get this boat back in the water.

As always, many thanks to Spannerman.

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All back together and running like a peach.

Launched last Wednesday, had two faultless trips from Hamble to Cowes and back, and so far all is good.

Thanks to all for your assistance, but especially spannerman!!
 
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