merc 165 lower unit leak

[83mulligan]

I have a small amount of gear lube coming out of the small (1/8") hole at the front of the lower unit housing on the top side of the rounded part of the housing. What does this indicate? I changed the water pump this past summer.

 

[Don S]

Re: merc 165 lower unit leak

Drain the gear lube, then do a pressure check of the drive and see where it's leaking.
Did you replace/or loose the small quad ring next to the water pump? It seals the oil passage between the upper and lower units of the drive.

 

[83mulligan]

Re: merc 165 lower unit leak

no, i made sure i installed the quad ring. when i got into it, i found some melting on top of the lower half of the pump. I didn't have the part to replace it so i went ahead with the pump installation. I checked the gear lube several times after running it because i was worried it wouldn't seal up right around the shaft. There was never any water in the gear lube, but there were some tiny pieces of gasket material in the lube. Though, i thought there was some overhang on the gasket material when i installed it.

 

[Don S]

Re: merc 165 lower unit leak

i found some melting on top of the lower half of the pump. I didn't have the part to replace it so i went ahead with the pump installation.

I remember reading something about that process before, let me think, where was it. It was something like this:

Why is there never enough time to do it right the first time,
But always enough time to do it again? ​

 

[83mulligan]

Re: merc 165 lower unit leak

i was on an island far from a marina superstore. It was that or waste the whole weekend.

Anyhow, what is that little hole i was describing there for?

 

[Bondo]

Re: merc 165 lower unit leak

Anyhow, what is that little hole i was describing there for?

Ayuh,..

It's a weep hole for draining water out of the cavities of the housing,...
Or oil in your case...

 

[83mulligan]

Re: merc 165 lower unit leak

So, i need to replace the bottom half of the water pump. Anything else I should look for when i'm in there? What about pulling the whole drive and looking at the spline shaft and alignment, then resealing that. Is that a huge job?

 

[ziggy]

Re: merc 165 lower unit leak

imho,
yes, replace the lower part of the water pump. the upper half too. and the impeller. from what i've read here. most suspect for the lub out the water drain hole in the ft. of the drive would be the shift shaft seal, from what i've read. i've never done one, check out the service manual for R&R. do what dons' say though. pressure test the drive. this will confirm the leak location before you assume where the leak is. if you had a meltdown from impeller failure, taking out the lower waterpump housing. i'd think ya have many checks to do.. find as many fragments of the impeller as ya can. check for meltdown of the waterpocket cover (don't touch these bolts, they break off easy). check for oil seal wear on the drive shaft. bellows between the riser and the exhust pipe may be melted too. flappers melted and gone?
ya don't have to remove the drive to do these deeds. though if ya've not removed yer drive for a while. do remove it. do the checks in the book. gimble brg. smoothness + grease it. check alignment, grease ujoints, grease coupler, inspect all bellows, grease shift slide assy. probably more stuff i can't remember at this time too. others will chime in if i'm leading ya astray or theres others items i've forgot....
as for a big job. one thing leads another... start reading the service manual. much info in it...

you do have yer service manual from the adults only sticky don't ya?

assuming ya have the bread. i'd use mercruiser parts too. they work best, if ya can afford them in this day and age...

 

[83mulligan]

Re: merc 165 lower unit leak

Here is a picture showing the condition of the lower water pump housing and gasket when i opened it up. Is there something on the shift part that i may have missed resealing that I should look for when i replace the lower pump housing?

 

[Don S]

Re: merc 165 lower unit leak

No way of telling where the problem is from that picture.
If it were me, I would plug the oil passage hole, put the upper housing on the water pump and pressure check the lower. Also look at the seal in the upper where the input shft goes.

 

[83mulligan]

Re: merc 165 lower unit leak

ok, so if i pull the whole outdrive, you guys can assist me in going through the check points and getting it back on properly???? I can take lots of pictures, maybe help someone out down the road.

 

[ziggy]

Re: merc 165 lower unit leak

ok, so if i pull the whole outdrive, you guys can assist me in going through the check points and getting it back on properly???

of course. that's what this forum is about. helping ea. other out. these guys here have helped me out on multiple occasions. i reckon i'll need some more help to in the future too.
do go get your service manual at the adults only sticky though. and read it. many questions will be answered there. come here to clarify that your reading and comprehending.... these guys are great here. i think they just like boats and engines....
for starters. pulling the whole drive is yearly preventative maint. per the service manual. it'll also tell you need to grease the ujoints, grease the gimble brg. + inspect it for absolute smoothness. also that you need to run a alignment bar into the coupler through the gimble brg. to assure alignment. this will be a must have tool. the alignment bar. then you can accomplish this task. if your unsure how to use the alignment bar. come on back and you'll get many answers i'd bet.... there are other things to inspect also along with what few short items i pointed out. the service manual points them all out. good luck with your project...

 

[83mulligan]

Re: merc 165 lower unit leak

Ok, great. It's a little intimidating to me, but I want to do it so that I can be comfortable doing the yearly maint. on it myself. Even with the service guide this summer, there were a lot of extra gaskets and parts in the water pump kit (for other outdrive models i assume) and it really made me question whether I used all the right ones. I also want to check my alignment and the condition of my spline shaft, grease and inspect gimbal bearing and on and on. I want to have peace of mind when I launch her this spring that the outdrive is in as good a condition as I can have it in. So, I'm game.