Small oil leak in Cobra drive unit

[Black as]

Hi Guys
Need some advise, I imported into Australia a 1988 2250 cobra Capri with a 350 chev along with a cobra stern drive. Over the past month I am giving the boat a complete work over checking everything before it hits the water. About 2 weeks ago I checked the stern drive oil level and it was down about a 1/2" so what I did is drain the unit and replaced it with new oil. So from when I bought the boat and then receiving it took around 6 months and there where no leaks upon arrival, but since I've put in the new oil I have found a few drips on the garage floor, so I removed the prop and had a good look and tightened the 4 bolts inside the lower leg and got about a half a turn out of each bolt. But when I received the boat there were no signs of oil in the lower leg??? The oil I used to replace the old was a quicksilver brand 75w90.

The bottom inner casing with the 4 bolts attached looking at drawings show a ring seal on the casing, may be this is the cause, not sure? can anyone give some advise, I have some ideas but is this common and what is the best way to tackle this.

 

[Don S]

Re: Small oil leak in Cobra drive unit

Best thing to do is drain all the gear lube out, and do a pressure test of the drive and see what is leaking. When you get it pressurized, you may be able to hear it, if not, use a spray bottle of water with a little dish liquid in it. The bubbles the leak blows will tell the story.

 

[Black as]

Re: Small oil leak in Cobra drive unit

Best thing to do is drain all the gear lube out, and do a pressure test of the drive and see what is leaking. When you get it pressurized, you may be able to hear it, if not, use a spray bottle of water with a little dish liquid in it. The bubbles the leak blows will tell the story.

The thing is Don, I already know where the oil is coming from can you elaborate what the pressure test is going to tell me?

 

[Don S]

Re: Small oil leak in Cobra drive unit

The bottom inner casing with the 4 bolts attached looking at drawings show a ring seal on the casing, may be this is the cause, not sure? can anyone give some advise, I have some ideas but is this common and what is the best way to tackle this.

Well, it sounded to me like you weren't sure. But if you are sure that is where it's leaking, fix it. Either reseal or replace it if it's cracked or corroded.
Not sure what other answer there is.

 

[Black as]

Re: Small oil leak in Cobra drive unit

Well, it sounded to me like you weren't sure. But if you are sure that is where it's leaking, fix it. Either reseal or replace it if it's cracked or corroded.
Not sure what other answer there is.

Don, do I need any special tools to remove the inner casing at the prop shaft that has the "o" ring seal in it.

 

[Don S]

Re: Small oil leak in Cobra drive unit

What you need is an OEM service manual. Not a Seloc or Clymers.
BUT, if you want to look at a Seloc, there is a download for it up in the Adults only sticky at the top of this forum. At least it will give you some idea what you are about to get into.

 

[Black as]

Re: Small oil leak in Cobra drive unit

What you need is an OEM service manual. Not a Seloc or Clymers.
BUT, if you want to look at a Seloc, there is a download for it up in the Adults only sticky at the top of this forum. At least it will give you some idea what you are about to get into.

Thanks Don I will down load it tonight.

1 more question Don,I'm going to set the timing on my 350 4 barrel Chev tonight would it be safe setting it at 9 deg B.T.D.C. I'm running 98 Octane fuel