1974 Evinrude 115 hp outboard leaking oil question. With pictures.

[Bmw M3 Guy]

Today I looked under the prop and there was a puddle of oil. At 1st I thought it was the final drive lower unit oil. Maybe a bad gasket or a loose bolt from the side. It appeared to be leaking between the prop and the lower unit. 1st I took out the two bolts on the right hand side of the lower unit seen in the pictures below and let it drain. After completely draining I decided to take off the prop. Sure enough I noticed a collection of oil and smelled to be unburned 2 stroke oil. Since the prop is used for the exhaust I felt everything was ok. I know you guys are the experts and would like your input on this with viewing the pictures below.

The boat was last taken out 3 days ago and everything functioned correctly. Power was there and gas is always mixed properly.

2 question I have is this normal for oil to leak?

Also, since I drained the lower unit final drive, how much oil is required upon re-fill?













Thanks,

Justin

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[Bmw M3 Guy]

Also what is a good final drive oil to use?

[F_R]

It is completely normal to get unburnt fuel dribbleing out the exhaust. That motor can live with generic outboard gear lube from Wal Mart. While you are there buy one of those nifty little pumps to put it in.

[ezeke]

When the gearcase oil turns black as yours has, it is worn out and needs to be replaced.

The vent plug, which is identical in size to the drain plug, must be removed to properly drain the unit.

The motor must be in the running position to properly drain.

To completely drain may take 1/2 hour, especially if the weather is cold.

The gearcase capacity is listed as 27.9 ounces, but the unit is full when the oil spills out of the vent hole at the top when filled from the drain hole below.

[Willyclay]

Put new o-rings on both of the gearcase drain plugs when you reinstall. I personally like the allen-wrench replacements that are available. Good luck!

[DJ]

Put new o-rings on both of the gearcase drain plugs when you reinstall. I personally like the allen-wrench replacements that are available. Good luck!

Agreed! I use OMC/BRP "Hi Vis" in my John/Rudes. I like OEM stuff.

Also do a "decarb" which is described in engine FAQ's.

[HighTrim]

Worth a read for you.

http://forums.iboats.com/engine-frequently-asked-questions-faq/oil-leaking-around-lower-unit-iwombat-207285.html

[Bmw M3 Guy]

Worth a read for you.

http://forums.iboats.com/engine-frequently-asked-questions-faq/oil-leaking-around-lower-unit-iwombat-207285.html

Perfect thank you!