Mercruiser 165 leaking... possibly out of outdrive?

[jimmwaller]

Hi all,

I have a new-to-me Mercruiser 165. I've had it out the last few days trying to test things out, etc. Just been backing it into the water on the trailer to check everything!

This morning, same deal. Had it backed into the water when I noticed that the bilge was filling up. I thought it was the drain plug, but when I looked closer, it looks like there is a leak coming from the outdrive.

The thing is (and take this with a huge grain of salt, because I'm very new to the whole i/o thing), i don't think it's leaking from the outdrive seal. I went around to the stern and the sealant around the keyhole looked pretty good. I know that normally you can't exactly tell just by looking, but this leak was.... fast. It was actively dripping?not a steady stream, but pretty close. I bet I would have gotten a cup every 2-3 minutes or so. I think it would have taken a pretty big hole in the sealant in order to get that fast of a leak.

The other thing is, it seemed to be coming from actually inside the outdrive, where it comes through the transom. The leak is up high?it's not like it just pools in the transom, it actually drips. I can't see exactly where the drip starts but it's at least up around where the coupling connecting the outdrive to the motor. Also, it's coming from the middle. If it was the keyhole seal, I would assume that it would come from off to the side?


I know this is totally vague. I feel pretty sure that nobody will be able to say, "this is definitely what your problem is", but maybe people have some idea of likely things that I can check? Like, could leaky bellows cause this? Or is there some other membrane that may have ripped? Or other possible culprits?

Any help would be appreciated. Thank you!

 

[alldodge]

There shouldn't be any sealant around the outside of the transom assembly, it is not needed if the transom is solid and seal is good.

Noting where your seeing the water, I would think either the boots or upper pin shaft.

Has the boots been replaced?

 

[jimmwaller]

hi alldodge, no nothing has been replaced?yet. planning on doing so this week. So you think it's likely that it's the boot (is this is the same as bellows), which should be a maintenance item anyways?

thanks

 

[Bt Doctur]

 

[kenny nunez]

If the water is not coming in from the above pointed areas you may have an electronisis hole just above one of the studs . Raise the drive and push it to either side and look with the brightest flash light you can get inside the upper cavity @ the 11 or 1 o'clock position for a hole, you can sometimes put a finger and feel for it.

 

[jimmwaller]

thanks for the information. I should have mentioned, I have no idea what I'm doing with i/o motors.... i've only used outboards up until this point. So, while that photo would probably be really helpful for most people, I have no idea what I'm looking at. Let me see if I have this right: Is that the face of the outdrive upper that stays on the transom, and so the rest of the outdrive would get bolted to that face? And the arrows are showing where I should be looking for water?

And then, kenny, you're saying that IF it's not coming from one of those two areas, I may have corrosion near one of the studs, so I should check there?

thanks!!

 

[Bondo]

Ayuh,.... BD's picture is of the piece that's right behind the motor,...
The motor mount plate ain't on it, but that's just inches from the motor,...

If yer bellows is leakin',...
It's vent into the hull is seen in that picture,....

 

[jimmwaller]

Oh, I see. So that plate is on the INSIDE of the transom? So if I peek in there with a flashlight, I should be able to see water dripping from that hole, if the issue is my bellows?

That seems definitely possible... that hole looks like it could easily provide for a fast drip.

thanks!!

 

[kenny nunez]

Hopefully it is the driveshaft bellows that is the leak. With the drive up look closely on the bottom and sides of the bellows that is where the holes show.

 

[Blueghost924]

Pictures would be great if you can get some!

 

[jimmwaller]

Thanks kenny, I will take a look where you suggested!

Blueghost, I will take photos. Anything in particular that would be helpful?

thanks

 

[Bt Doctur]

most leaks occur from:
electrolysis hole, a hard bottom strike breaking the anode bolts on the bottom, transom leak from disturbing the mounting gasket during a hard strike, leaking exaust pipe, leaking shift bellow, leaking main bellow., gasket leak at trim line entry cover

 

[jimmwaller]

here are some of the outdrive where it meets the transom

 

[Bt Doctur]

Thats a very old transom 165 should be the inline 6 cylinder

 

[jimmwaller]

yep, it's the inline six. does that tell you anything useful?

After thinking about it more, I'm less convinced it's the transom and more convinced it's the outdrive. I guess I didn't specify earlier, but it doesn't "drip" and run down the wall?it actually falls through space and drips right into the bilge. I feel like if the transom was leaking, the drips would just run down the transom wall. But these drips were coming from somewhere further away from the transom, so that when the drip fell, it dripped down about 2 inches away from the wall.

BT doctur, I will look into some of the things you mentioned. If it's a bellow, is that something that should be visually apparent?

thanks again everyone for helping me figure this out!

 

[Bt Doctur]

when you remove the drive you should find water in the bellow, if the bellow is dry inspect the shift cable bellow for holes or damage.
Use good hose pressure and spray the outside while looking inside ,

 

[jimmwaller]

Just confirming....

I watched a youtube video on how to remove the lower unit. They took off the trim arms (one long pin/bolt) and then the six bolts that hold the drive to the bell housing.

https://www.youtube.com/watch?v=Mkl6hXEYnd0

Looks like that's what I do on mine, as well. But is there anything else I should be aware of? Hidden bolts, anything I could accidentally break?

Two more questions:

One, I may as well do all the maintenance while I have it open. I have a Mercruiser 165 (not exactly sure what year), is this the right kit?

http://www.iboats.com/Sierra-18-8205...BoC7Q8QAvD_BwE

EDIT: Just read a review of this kit on amazon, the reviewer says that it didn't fit their 165. Now I have no idea where to get a kit.... this one?
http://www.mercaftermarkets.com/merc...803097t-1-oem/
says it fits the MC-I, which I assume is the same as the MC1? But it also says that it fits 1977 and later, whereas I think mine is pre-1977.....


And two. In the video, they loosen the drive from the bell housing by lifting it and dropping it. Is this an accepted way to do this? seems like a lot of stress on the boat.

thanks!!

 

[jimmwaller]

whelp, mystery solved, probably.

Just went down to inspect the bellows... didn't expect much because they seemed to be in great shape—looked pretty new, PO said they were pretty new, and they felt good when I felt around.

But, upon closer inspection... looked way on the underside and found these giant rips!








I'm going to guess that these were causing my problem


Now I just need to find the proper kit.... Anyone with a 165 feel like chiming in about which kit has worked for them?

EDIT: Actually, I feel like I should just start a new thread for this question. Would be better to have the actual question in the subject line I think!

So, I'll consider this thread closed, and start a new one. Thanks for all your help everyone!!

 

[alldodge]

Good to hear you found the problem but sorry to find out folks lie like a big dog.

 

[kenny nunez]

How does the engine run? Before you start pulling this apart be sure the engine is in good condition.
The early models had a boot that was smooth on the inside where it mounted to the housings. The later has a raised bead that fitted in a groove on the housings.
Take a close at the pivot shafts and you will see that they are secured with what looks like a nail that is bent over on the front side of the gimbal ring. They must be removed before trying to pull the pivot shafts out. The shafts are threaded 1/4" 28 as a way to pull them out. Hopefully the driveshaft is not rusted to the gimbal bearing or you will not be able to remove the drive.