Lower Unit Adventures

I've been recommissioning a 1995, 115HP Yamaha after being in storage for 2 years and not serviced by the previous owner for at least 2-3 years before that.

It runs ok so far and the last problem area is the lower unit which hasn't seen service in 4-5 years.

Today I tried changing the water pump but have some issues. I got the impeller off after 2 hours of heat, prying and cutting but am stuck with the Woodruff key. It's severely corroded and chipped. So far I can't remove it. I've tried heat, WD40, and chiseling/punching but so far no luck. I'm worried it will chip to flush with the shaft. Any tips or just keep chipping away? I have to remove it to install the new bottom plate (the old one is destroyed)

Next when removing the impeller I found many pieces of a small spring. I think the goes in the oil seal. What's the part number and how do I replace it? I can't find a reference in the Seloc manual. Are there other parts I should replace at the same time (besides the water pump kit)?

Finally, I drained the gear case oil. Just under a quart came out and it's nearly pitch black. No metal in the fluid or on the drain plug magnet. Doesn't seem to be any water mixed in but I have it settling to see. Is this a sign of anything or just past due service?

Any advice based on all this? I want to get this fixed up and in the water ASAP.

Thanks
JP

Update

UPDATE: I got the key out by soaking overnight in PBlaster

I still don't know about the broken spring - any ideas?

Also no water separated from the gear case oil. It's just black

Thanks for any help
JP

[boats.net]

If the spring was inside water pump then it's probably from the drive shaft seals that is just below water pump. If it was on top of water pump then could be lower crankshaft seal.

Thanks. It was in the water pump housing so it must from the drive shaft seal. Can you post a link to the drive shaft seal spring? I'd like to order it and get it fixed. I don't see it explicitly listed in the parts diagrams.

I'm guessing I can just replace the spring.

Thanks
JP

you are better off to get a new seal then to find the spring. Trust me for the cost you are better to change the seal.

[Hamfisted]

Replace the seals...

You have to buy the complete seal, the tension spring is part of the drive shaft seal and not sold separately. It is very common for them to break after a few years, so check it whenever you replace the waterpump. Part number is 93101-28M16-00 and there are two of them back-to-back there. Whenever that tension spring breaks you end up getting water into the lower unit. There are two identical seals there, back to back, both with same type tension spring in them. It's usually the top one that has the broken spring so you may be able to just replace the top one and be fine. That makes it quick and easy. Just pry it out with a small screwdriver or tool.




- Mike

[Tucker]

Shit, something I didn't look for when replacing the water pump this weekend. Does it ever break and still stay in place? Hence not able to notice it. Does it alway pop out of place when it breaks? Cheez, something else to check.

Mine had 2 small pieces of spring (<1/8") in the impeller housing. Most of the rest of the spring pieces were still in the groove of the seal. There was no water in the lower unit when I drained the oil and the seals still seemed secure, but I try to be proactive.

I'm going to try to replace the 2 seals and o-ring tonight tonight anyway. Hopefully I can do it without special tools.

[Tucker]

I'd soak it in WD40 first. May come right out. Please post how this went. If it's no big deal I'll do it next water pump whether it needs it or not.