9.9 hp Johnson oil leaking from lower unit

I have a 1974 Johnson 9.9 hp. I cranked it today in bucket of water and afterwards when I removed bucket I noticed that oil was coming out of the exhaust holes on both sides of lower unit. Tomorrow I'm going to check my lower unit oil. I'm thinking this is not a good sign. I would appreciate any feedback.

It's pretty normal to see oil coming out of the exhaust. I'd say odds are there's nothing to worry about but it never hurts to be sure.

I would agree with JMichael, you should see some oil exiting the exhaust. If there was no oil leaving the motor it would mean it was all being burned and there would be no lubrication.

However, it is a simple matter to check the gear case oil and it is something that should be done routinely.

Thanks for the replies. I did not have a chance to check gear case today, I will do it in a few days.

It is not uncommon to see unburned fuel oil mix exiting/draining from the through hub exhaust or the foot of the gear case. This is normal. There are also weep drains near the water pump that allow unburned fuel and oil to drain to prevent build up and caking.

Drainage is usually blackish to grey emulsification because it has mixed with water.


Have fun on the water. Oh, at the end of each year, drain your gearcase and refill with 80 to 90wt marine grade gear oil. This allows you inspect your lower unit to make sure it is not allowing water to intrude. It also ensures that if there is water it is drained so that your gearcase does not crack or split during the winter. The freezing temps will cause expansion of water in the gearcase and draining each season naturally helps prevent rusting.