water in lwr unit

[skipper]

My impeller needs replaceing.(job I have done before) When I drained lwr unit Oil was milky. New oil was put in 2 months ago. What seals are the most likely to need replacements? Motor is a 1986 40hp. Also should I replace any bolts?
Thanks in advance,
Skipper

[Ken]

skipper,
The most likely area for water intrusion is the prop shaft seal - there could be fishing line wrapped around the shaft cutting into the seal.
There are seals and o-rings around the drive shaft and shift rod also. The lower unit has to be taken apart to get to the prop shaft seals and o-ring, and considering the age of your outboard, you need to replace all seals and o-rings at the same time. Best to get yourself a Yamaha shop manual to guide you along - you're gonna need some "special" tools like a ring-nut wrench and wheel puller - you may be better off letting a good marine mechanic take care of this for you.
Good luck,
Ken K

[skipper]

Thanks Ken,
When I pulled prop off, there was fishing line wrapped around shaft.

[Ken]

skipper,
You might try carefully pulling the line from around the prop shaft - the prop shaft seal may not be damaged too much - might reseal itself - worth a try.
Good luck,
Ken K

[Hank Austin]

Ken is right, I drained gear oil from lower unit on my 9.9 and found water. Pulled prop and found combo string and tough grass. Refilled with oil and have drained it twice since with no signs of water. Worth a try.