30hp Yamaha 1991 oil out of holes?

[jedimaster]

I was putting in new gear oil and when I was pumping it in the bottom, with the fill level screw out, Gear oil came out of two little holes? they look like vent holes or soemthing. Is this normal behavior? I am going to pull the lower unit back off and change the water pump, just wondering if I need a seal kit or something like that as well? Where would be a common place for gear oil to leak from? or where are the posible sources of leaks?

 

[99yam40]

Re: 30hp nissan 1991 oil out of holes?

Re: 30hp nissan 1991 oil out of holes?

Not sure if the nissan question should be in this forum, but sounds like you have a shaft seal completely out or a cracked case if it is anything like the other outboards I have seen.

 

[jedimaster]

Re: 30hp nissan 1991 oil out of holes?

Re: 30hp nissan 1991 oil out of holes?

Ooops, its actually a yamaha, Not sure why I called it a nissan.

 

[gettin'wet]

Re: 30hp Yamaha 1991 oil out of holes?

Wow, I just showed up looking for an answer to the same question. Mine is 1994 15hp. Gear oil seems to overflow out of those two small holes. They look like vents. Is this normal? Should the small holes be plugged or is there likely a seal to be replaced?

 

[jedimaster]

Re: 30hp Yamaha 1991 oil out of holes?

Still no answer, I checked the shift boot and it looked fine. I had lots of water in the gear oil as well. Trying to figure out where I should start replacing gaskets. Was gonna start with a water pump kit, but not sure where else I should be looking. Also on mine there is a plastic plate with two phillips screw on the bottom of the gear case, it is broken. What does this seal?

 

[gettin'wet]

Re: 30hp Yamaha 1991 oil out of holes?

Also on mine there is a plastic plate with two phillips screw on the bottom of the gear case, it is broken. What does this seal?

If you mean the small plate where the shift linkage passes through, then again, my motor has the same issue. Mine leaks LU gear lube because the screw is stripped. I have tried, but I don't know how to remove this plate or where to get a new one. (see pics)

I also attached a picture of the 'vent' holes in question, and a couple of the gear case. I hope these help. Also, if my pics don't help and you think they derail your thread please tell me and I can just delete them!

 

[jedimaster]

Re: 30hp Yamaha 1991 oil out of holes?

No sounds good to me. They are the same holes I have stuff leaking out of. But the plate I am talking about is underneath the casing on the outside.

 

[tomcat8263]

Re: 30hp Yamaha 1991 oil out of holes?

did you ever find out what these holes are for? i've had the same issue with oil leaking out of those while refilling as well.

 

[ralphnjoann]

Re: 30hp Yamaha 1991 oil out of holes?

I think they are simply drain holes mostly for water. Assuming there are no cracks or other problems in the casing, if oil is coming out of them, then there is either a leak which will require new seals where the drive shaft goes into the water pump, or oil is coming out of where the shift rod comes out. On my 1984 15hp engine, there is a corrugated rubber boot on the shift rod anchored by a plastic bracket and screw similar to what is shown in the pictures above. It's supposed to be fairly easy to replace these, but if you have to replace the seals around the drive shaft, it's a major pita. I would recommend a mechanic unless you are fairly skilled.