1999 40hp lower unit leak??

[wellsc1]

I've read numerous threads related to the subject, then "tried" in vain to find exploded view of lower unit propeller shaft to make sure correct parts are ordered. Before I try more, I want to determine if it's an oil leak or just unburned gas/oil.

I ran the motor one day to pre-test a tach before boring hole panel and mounting it. A few days later, I installed it and ran motor again to verify working tach with joy. Later that day I noticed the leak. It's really black and I certainly wouldn't expect LU oil to be that dark (LU oil may be about two years old).

I plan to smell it. I also plan to let out the drain screw just enough to get a small sample of oil to see its condition. Comparing the two should give double indication what residue it is. If it's LU oil, where do I find exploded view to order prop shaft seal (and maybe needle bearing), while I also order repair/service manual?

Any tricks of the trade?

Thanks.

 

[wellsc1]

Re: 1999 40hp lower unit leak??

BTW, it's a 1999 40elpt, Force by Mercury. I thought that may help focus any replies.

I never know when I'm looking at a Chrysler or Mercury Force with certainty.

 

[CapCramer]

Re: 1999 40hp lower unit leak??

Touch the fluid with your finger and smell it. If it smells like gas its normal as the exhaust exits around there. Gear oil has a distinctly different smell. if it leaks it usually is milky as water has compromised the gearcase and mixed with the gear oil. HTH.

 

[wellsc1]

Re: 1999 40hp lower unit leak??

I felt and smelled the oil leaking. It's certainly has no gas smell. It's black as black can get, almost like liquified grease (and about stinks like it). Next, I loosened the drain screw to let a little LU oil dribble out. It's almost clear as new oil the day it went in. Where do I go from here? I may change the LU oil to see if the amount that drained out equals the amount that is used to refill it.

In the meantime, I've ordered a manual to prepare for the worst - seals to replace.

 

[roscoe]

Re: 1999 40hp lower unit leak??

Normal exhaust residue drainage. Be happy thats all it is.

For your viewing pleasure:


http://www.crowleymarine.com/mercury_parts/2532/18.cfm

 

[wellsc1]

Re: 1999 40hp lower unit leak??

Roscoe, this cadet thanks you for the exploded view of the LU. My wife even prompted me to thank you. I think I'll go fishing soon.

 

[wellsc1]

Re: 1999 40hp lower unit leak??

An update and closure to this thread. It is unburnt oil. It's a good thing I changed the LU oil. It was honey clean, but about 5 oz. shy of full capacity. Now I know it's full and fresh. Many thanks!