'78 Johnson 9.9hp w/ some Issues

I have a '78 Johnson 9.9hp it runs pretty good, however I noticed some oil leaking from the lower unit where the prop is. Is this the prop shaft seal, is it hard to replace? I heard that it could also be excess oil from the fuel not being burnt off. I'm going to drain my lower unit oil and see what the oil is like.



Also, I took my lower unit apart to look at why my water pump wasn't working and noticed that there was water and excess junk in the front cavity where the shift rod is located, the drain hole probably was clogged, it was more like thick grease than oil. Could this be coming from the prop area?



Any suggestions on either issue?

While you have it apart replace all the seals & be done with it.Don't forget there is a seal below the water pump & the seal on the prop shaft is an easy fix.Also check the shift shaft seal.
Make sure all the drain holes are cleaned out of the lower unit.

crazymanme2 said:

While you have it apart replace all the seals & be done with it.Don't forget there is a seal below the water pump & the seal on the prop shaft is an easy fix.Also check the shift shaft seal.
Make sure all the drain holes are cleaned out of the lower unit.

Click to expand...

Thanks, any info or tips on replacing these seals?

No they're pretty straight forward.The shift shaft seal could be a problem if it needs to be replaced but the others are pretty easy.Just make sure you put the seals facing the right way with the lip.

What you are seeing is more than likely unburned fuel/oil. When you removed the propeller was there any seal damage from fish line, etc.? By now you have had time to check the oil in the lower unit. Was there water in it? If not then you are pretty much good to go. The sand and junk in the cavity forward of the pump is pretty normal for an engine that has been run and beached or run in shallow water from time to time. If still in doubt....before re-sealing the gearcase you may try simply going into a dealership and have them pressure and vacuum check your lower unit. Lots cheaper than resealing for the heck of it.

Pappy said:

What you are seeing is more than likely unburned fuel/oil. When you removed the propeller was there any seal damage from fish line, etc.? By now you have had time to check the oil in the lower unit. Was there water in it? If not then you are pretty much good to go. The sand and junk in the cavity forward of the pump is pretty normal for an engine that has been run and beached or run in shallow water from time to time. If still in doubt....before re-sealing the gearcase you may try simply going into a dealership and have them pressure and vacuum check your lower unit. Lots cheaper than resealing for the heck of it.

Click to expand...

I drained the lower unit this weekend and the oil looked like it hadn't be changed in a long time but there didn't seem to be any water and it look totally different then what was leaking from the prop. Now, while dropping the lower unit to look at my water pump I noticed that 2 of the bolts that hold the lower unit on were headless. I tried to remove 1 but it was seized, any tips on removing these headless bolts?

Good information that your gearcase is not leaking! Now, if the sheared fasteners are flush with the exhaust housing casting the only way to remove them is by drilling them out. If they still have enough sticking out to where you can grab them with a pair of pliers then get yourself a MAPP torch at the least and heat the housing around the fastener until well after the paint has blistered and burned off and slowly twist them back and forth until they begin to loosen. If you are forced to drill, get a cobalt drill or better and drill at a low rate of rotation using alot of pressure. Stainless is a very soft metal normally until it is cold worked. By this I mean that if you hit it with a hammer, drill it with a drill bit, etc. it will work harden ahead of the tool you are working it with (kinda' cruel isn't it...) so by going slow with alot of pressure you can remove what is being worked and be in fresh stainless as the bit turns. Takes practice but fortunately you only have two bolts to remove. After removal you need to drill and tap for a heli-coil.