Lower unit oil leak ?

[1arunem]

Hey guys, I have a 1986 Evinrude 70hp outboard. I had the boat/motor stored in the garage in the 'up' position. I lowered it and after an hour or so noticed a pretty good spot of oil underneath the prop. The oil was very clean and appeared to be coming from the prop area.

I assume there is a prop seal of some sort. If so, how difficult is this to change?

Thanks in advance for your help!

[Bamby]

First things first... Oils all have their own unique odors for the most part, are you familial with them? If so stick the tip of your finger into the puddle and then take a whiff or smell it, to help determine where it's migrated from. Sometimes it's a bit of engine oil or two stroke that's migrated down to the lower unit to seep out. But then it could be a lower unit seal as you suggested but a sniff test is the first diagnostic step that should be taken.

[1arunem]

The oil has the consistency and smell of gear oil (or dope as many call it). It was very clean (fairly clear) and not similar to two cycle oil.

[Bamaman]

There are a number of seals on the lower unit--down by the prop and on the inside where the drive shaft and the gear shift shaft go into the lower unit. (You cannot see'em.)

Every so often, you need to have the seals vacuum and pressure checked by a qualified marine mechanic. The seal kit may be something like $85, but it's about a 2 hour labor job. Total seal job can push $300.

The penalty for ignoring your lower unit is the gears, etc. will be toast. I have a perfectly good Yamaha 115 hp 2 stroke engine that's missing a lower unit (junked.) You wouldn't believe how much a new l/u costs from the manufacturer. A Mercury 250 XS Pro new lower unit is over $5,000.

[Drifter]

Take the prop off and check for leaks. You may find fishing line has wrapped around the shaft and damaged the seals. I put some in a yamaha 115 4 stroke and it was pretty easy. Not sure on your engine though. You Tube usally has good video for just about everthing. Good luck.