1964 28 HP Johnson lower unit

[chi_town60608]

1964 28 HP Johnson model RX-12, Serial # J2455104

I've gotten to the lower unit in my tear down. It's not quite like most I've seen on the internet in that it has 2 parts that must be removed. A bottom section approximately 5 inches tall and then another approx. 5 inch section. I got those apart and removed the lower unit and a wasp nest fell out. It doesn't look to bad from what I can tell, but I do have a couple of questions. These is a copper pipe that couples to a copper pipe in the upper unit that transports the water. Is this normal? It def. looks original, but I wasn't sure if there is an upgrade I should do or any kind of maintenance on the pipe to do. Next question is in regards to the propeller. It looks fine to me, but I thought I would get the opinion of some of you more experienced guys. Also, from the info I've gotten off the web, there is supposed to be some kind of ring at the top of the shaft by the gearing; mine didn't have one. It appears there's a groove for one, but there wasn't one there. Another thing different from what I've read is that there is usually a key that the propeller slides onto. This one didn't have a key, it just has a protruding circular piece of metal that it slides over. Lastly, I was looking up into the motor once the lower unit was off and noticed a mud dauber nest attached to the shaft. I've marked it in one of the pictures. Is there a best way to get this out of there? Or maybe put differently, is there something I SHOULDN'T do to get it out? I figured I'd just take something and knock it off and then blow it out with an air attachment, but I wanted to make sure that's ok. Lastly, if I haven't came to a drop of oil, does that mean this one didn't have any in it? I mean, it could've been sitting for years for all I know, I just wanted to make sure there's no 'magic' compartment full of oil that I haven't gotten to yet. If any of you see something that needs attention that I haven't mentioned, feel free to mention it.






















Thanks again!

chi_town

 

[Grub54891]

All them parts look normal to me. I have the same motor. They could use a bit of cleaning up! If the pic with the arrow is a dauber nest,poke it out with a coat hanger,it'll be ok as long as they didn't get up into the motor. The lower gear-case should have oil in it,find the drain and fill screws and take them out. The oil should be carmel colord or so. If milky it needs a reseal. Easy to do on them. Good luck,keep us updated! And by the way, that 28 one of the smoothest runners I've seen from that era.

 

[F_R]

See the wear on the splines at the top end of the drive shaft? That is because that motor has been running with the o-ring missing (the one that goes in the groove). The o-ring keeps water out of the splines and grease in. From the looks of it, you will be lucky if the matching splines in the crankshaft aren't rusted away, or nearly so. It's all over when they are rusted away. (Crankshaft is steel, and rusts, unlike the stainless steel drive shaft)

 

[chi_town60608]

From the looks of it, you will be lucky if the matching splines in the crankshaft aren't rusted away, or nearly so. It's all over when they are rusted away.

So, is there any way of telling if that is true without pulling the engine off? I'd realllly rather not do that, but if it needs to be done, I will.

 

[racerone]

The arrangement of the copper tube into the other tube means that the motor had a kit installed to change it from a short shaft to a long shaft motor.

 

[chi_town60608]

The arrangement of the copper tube into the other tube means that the motor had a kit installed to change it from a short shaft to a long shaft motor.

Is that setup ok or should I be looking for something to do it 'right'?

 

[Grub54891]

You can go up there with a boroscope and have a closer look.then determine if you have to pull the powerhead.If the splines are shot,you will need a new crankshaft. Bummer. Them splines are supposed to be greased before assembly.

So, is there any way of telling if that is true without pulling the engine off? I'd realllly rather not do that, but if it needs to be done, I will.

 

[F_R]

It isn't all that hard to pull the powerhead. Well that is if the screws aren't all seized & corroded.
Nothing at all wrong with a long shaft extension kit. Factory dealers sold them.

 

[racerone]

????---Why would you think there is something " wrong " with the water tubes ????

 

[racerone]

I also must say that you need to remove the powerhead to deal with the " scored piston " on this motor.---Water tubes are insignificant compared to a scored piston.----Water pump has been driven by that little pin since these motors left the factory !