yamaha 150 salwater II series outboard gear oil leak

[slsmithmp]

I have a 1998 Yamaha 150 saltwater II series outboard that I recently (2 weeks) changed the gear oil in with no problems. Took the boat to the water this weekend and it performed well. After clean up and parking of the boat, the lower unit is leaking gear oil by the prop (not by either plug for changing the oil). It only leaks when the motor is fully lowered. When I put a slight trim on the motor, the gear oil does not come out. There does not appear to be any water in the gear oil (it has the same smell, texture, and color as when I replaced it). Any help is greatly appreciated.

 

[brentjsimm]

Re: yamaha 150 salwater II series outboard gear oil leak

it sounds to me like your lower unit seal/s or gasket/s may need to be replaced. i would drain the gear oil, take off the prop, then start to disassemble the lower unit until you have the problem identified. i'm a weekend warrior with outboards, so you may get some better suggestions. the gasket/s or seal/s would be my guess though. how has the boat been stored since 98?

the link below is a good place to go to identity your parts. once you select your motor, check out the "repair kit 2". that will have the gasket kit, or the individual seals listed. once you have the individual piece that may be damaged identified, you can purchase it from iboats, or replace all the gaskets with the kit. the entire kit is around 60 on this site, which i've found to have great prices, or individual seals as cheap as 5 bucks. good luck!
http://www.boats.net/parts/search/Yamaha/Outboard/1998/parts.html

 

[slsmithmp]

Re: yamaha 150 salwater II series outboard gear oil leak

thanks much. now i have somewhere to start. Hopefully, I don't get in over my head and have to drag it to a shop.

 

[brentjsimm]

Re: yamaha 150 salwater II series outboard gear oil leak

You'll be fine. Just go slow, and it doesn't hurt to take tons of pictures as you go. If you don't have a manual, I would suggest getting one. I have a 91 Yamaha. It seems that between this site and a manual, I'm capable of a lot more than I thought I was. It beats paying a mechanic for smaller things.

 

[rodbolt]

Re: yamaha 150 salwater II series outboard gear oil leak

remove the prop, inspect carefully.
sometimes its the drive shaft seal thats leaking not the prop shaft seals.
pressure test the unit.
once the leak is identified then make a plan.