LU oil looks like chocolate milk

[Plainsman]

I had new impeller and seals put in by the Merc man in the spring, does this indicate bad seals or something worse?
TIA,
Eric

 

[DJ]

Re: LU oil looks like chocolate milk

Don't condemn anything until you change the fluid and replace the fill and drain plugs screw seals. That is the most common area for a leak.

 

[Plainsman]

Re: LU oil looks like chocolate milk

There was no seal on the fill screw. It also looks as if the prop shaft is bent. Where the prop is in the housing, the paint is worn off in one spot. If I turn the prop by habd, I can see where there is a gap everywhere except where the paint is worn off. :'(

 

[JUSTINTIME]

Re: LU oil looks like chocolate milk

u need to vaccum test and pressure test the lower unit

 

[Paul Moir]

Re: LU oil looks like chocolate milk

That doesn't necessarily mean the propshaft is bent. There's lots of reasons that could happen. You have to measure the propshaft runout to determine if the propshaft is bad. Besides, it's impossible to bend the propshaft without knowing it. You would also have to have destroyed the propeller.

No fill screw gasket? Who did the last oil change?

 

[Plainsman]

Re: LU oil looks like chocolate milk

That doesn't necessarily mean the propshaft is bent. There's lots of reasons that could happen. You have to measure the propshaft runout to determine if the propshaft is bad. Besides, it's impossible to bend the propshaft without knowing it. You would also have to have destroyed the propeller.

No fill screw gasket? Who did the last oil change?

What is the propshaft runout? The Merc dealer did the last oil change in the spring.

 

[Paul Moir]

Re: LU oil looks like chocolate milk

If you plan to continue using that dealer, you might want to consider asking him about the missing gasket and gauge his response. Personally I'm usually willing to overlook an occasional mistake as long as the other party owns up to it.

Runout is just the measure of how bent the propeller shaft is. It's normally measured with what is called a "dial indicator" as the tolerance is just a few thousands of an inch.
But you cannot hope to measure it without first removing the propeller as the propeller could be unbalanced, the rubber hub could be somehow off, etc.

I hope to hell (odd expression, eh?) that you don't have any side to side play in the propshaft. That can be caused by insufficient lubrication.

 

[Plainsman]

Re: LU oil looks like chocolate milk

Thanks for the explanation Paul. There is no side to side motion.

As for using him, he is the only Merc dealer within 200 miles. Guess I need to learn to change the impeller and seals myself. I'm up to learning. I really enjoy working on it, and learning all about the boat and motor, for now, is fun for me.

 

[gss036]

Re: LU oil looks like chocolate milk

You could very well just have a bad seal either at the prop or the drive shaft in the lower unit. Not an expensive but it is best left to someone with experience. Follow the above advice first and change the seals behind the fill and vent screws. Then if it still gets milky have a pressure check done and it will show where it is leaking.

 

[Plainsman]

Re: LU oil looks like chocolate milk

Thanks Gary. I won't be able to get it out in the water until next spring, no water within a couple of hours from here, and that is even iffy.

 

[gss036]

Re: LU oil looks like chocolate milk

That being the case, definately change the oil to make sure you don't have any water in there to freeze up and crack the housing, you guys get some real cold weather there in Nebraska.