i noticed some oil dripping out from under the prop. is there a seal in there when you pull the prop off and if so how would i go about changing it? it is a 1989 johnson 120 v4.  thanks

There are no seals when you take the prop off, but there are seals on the prop shaft, in the lower unit. You probably got some fishing line around the prop. It is know for cutting the seals on the prop shaft. If oils is coming out, than there is a good chance that water is going in. I would have the lower unit seals replace, All of them, if your not sure how to have a shop do it. also since you have it apart to put new seals on, I would put a new impeller on it too.

its normal. its left over oil coming out the exhaust.

i checked the oil and it wasnt milky looking and didnt smell like the gear oil. its probably build up exhaust oil. thanks

I'd replace the seals if I were you.  I once found a tiny, dime-shaped dab of oil under my engine.  Just out of paranoia, I took it to the shop. Turns out the seal was bad and my lower unit was full of water!  

Fortunately, I caught it early enough and there wasn't any damage.

Go get it checked out.  It's CHEAP insurance compared to the repair bill.

If your seals are leaking your lower unit oil will be milky. Your boat mechanic can check the lower unit seals with a low pressure air test. I say low pressure because if too much pressue the seal will collapse on to the shaft and seal not showing a true defective seal.