77 johnson 115 upper bearing seal

[whitejamie99]

I just finished a flywheel removal and when I inspected the upper bearing seal, it appears to have a small gap between the seal and the crank. The gap is not uniform around the crank. The timer base needs to be replaced but I dont want to put the flywheel back on until I know whether I have to replace the seal or not. Do I have to tear the top of the power head down to replace this seal?

 

[F_R]

Re: 77 johnson 115 upper bearing seal

The metal part of the seal does not touch the shaft. But the rubber part certainly does. Which part are you speaking of?

If the seal needs replacement, the bearing head can be unbolted and pulled out of the case. Then you can knock the seal out and replace it. Better order a couple of new o-rings for the bearing head to make it easy to reassemble. Oil the seal & o-rings before putting it back together.

 

[whitejamie99]

Re: 77 johnson 115 upper bearing seal

Thanks FR. I'm speaking about the rubber seal. I cant get the upper crankcase head assembly off - it seems to be stuck. Am I supposed to pry off the assembly? The 4 bolts are off along with the 4 screws that hold in the timer base. I think Im just afraid but do I need to use some more force? Will a puller work?

 

[whitejamie99]

Re: 77 johnson 115 upper bearing seal

I cant get the crankcase head assembly to break loose. I have removed 4 bolts and 4 screws (that mount the timer base). The assembly rotates clockwise and counterclockwise but will not come off. The pic in the manual looks like there are threads on the bottom? Manual says to "remove six screws" and then later says to "remove crankcase head from crankshaft". Is there a trick to this??? Is there some kind of penetrant needed? IM STUCK AND NEED HELP

 

[emdsapmgr]

Re: 77 johnson 115 upper bearing seal

The 1977 factory service manual shows the upper crank bearing housing being removed during the complete teardown and splitting of the crankcase halves. It shows a punch being used to drive the seal out from the inside of the housing. Does not help much in your situation. I'd be inclined to try to extract that seal from the top when still on the engine. Since the seal will be replaced, it is of no consequence if you damage it during extraction. You could try to deform it and grab it with a pair of pliers. Be careful, as you have the polished crank there and a bearing just underneath. You will want to put some OMC gasket sealer on the outside edge of the seal before you reinstall the new one. I'd also check the upper bearing to make sure it is not permitting the top of the crank to "wobble." If that upper bearing is going, the crank rotation can enlarge that seal over time.

 

[F_R]

Re: 77 johnson 115 upper bearing seal

I cant get the crankcase head assembly to break loose. I have removed 4 bolts and 4 screws (that mount the timer base). The assembly rotates clockwise and counterclockwise but will not come off. The pic in the manual looks like there are threads on the bottom? Manual says to "remove six screws" and then later says to "remove crankcase head from crankshaft". Is there a trick to this??? Is there some kind of penetrant needed? IM STUCK AND NEED HELP

It is a snug fit in there, and has two o-rings around it, but should come out. If you can rotate it back and forth, all the holding fasteners are out and it is not clamped too tight to remove. I hesitate to tell you to pry on it etc., because I don't want you to bend or break it. But the truth is, there is enough friction that you won't be able to simply lift it out with your fingers. Use a little bit of common sense and do whatever it takes to pull it out without destroying it. A puller might be a good idea. I've removed them by simply rocking them out with a pair of screwdrivers---like I said, use common sense and don't break it. Most of it is very durable, but the flange where the screw holes are is pretty thin.

 

[whitejamie99]

Re: 77 johnson 115 upper bearing seal

I have learned a new word not previously in my vocabulary. PATIENCE. Thanks FR for the sage advise and to use common sense. The O rings were providing the friction that held the assembly tight. Once I got past the first o ring it made a pop like the flywheel. The second o ring didnt scare me near as much. Then it was just a matter of working the assembly carefully with two screwdriver type pry tools and taking my time. This part is a lot like the flywheel and you just need to be patient and not do anything rash - it will come off.

 

[F_R]

Re: 77 johnson 115 upper bearing seal

Whew! I was afraid you'd break it and blame me. heh-heh.