Late 70's Johnson needs motor mounts and lower unit seal?

Thanks for reading my post. Any suggestions you have would be appreciated. We Bought this late 70's Johnson Sea Horse 35 HP motor for $200 "as is". We gambled buying it without hearing it run. It needed a fuel pump, water outlet elbo, and the fuel inlet connector. We replaced all of those parts (used $30) and the motor fires and runs great.

What we have now are 2 issues. #1 The seal between the lower unit (as shown in the pic) is not sealing. When we changed the lube, it was milky. Also, when running it on the water ears, we're seeing bubbles from the seam. I am pretty sure the unit has been serviced based in the new bolts, and it seems the water pump pumping really well. It just wasn't sealed well. We're pretty mechanical, but I've never torn a lower unit off an outboard...

Second problem. The motor mounts are wasted. There's way too much play. Where can I find some (new or used?). Also, can I loosen the outer bolts and tilt the unit forward to get to the inner bolts? (I'm sure my terminology is off here :roll: )

For your first question, you can buy new lower unit seal kits. You can probably purchase only that top seal, but you may as well re-seal everything while you are down there. On my '75 Johnson 10, I also had to replace the plate that the seal sets in, as it was so corroded it broke apart when removing the old seal. I posted a wanted ad on a vintage outboard classifieds site and someone had them NOS (new old stock).

I haven't had to do motor mounts yet, so maybe someone else can help with that.

Gamefisher said:

For your first question, you can buy new lower unit seal kits. You can probably purchase only that top seal, but you may as well re-seal everything while you are down there. On my '75 Johnson 10, I also had to replace the plate that the seal sets in, as it was so corroded it broke apart when removing the old seal. I posted a wanted ad on a vintage outboard classifieds site and someone had them NOS (new old stock).

I haven't had to do motor mounts yet, so maybe someone else can help with that.

Click to expand...

I am a backyard mechanic (cars, lawnmowers etc). Will I need special tools to replace this seal? If I remove the bolts, will the lower unit simply slide out and I can drop in a new seal, or is it more involved than that (meaning I'll be taking it to a shop)?

First you need to get a manual
https://www.clymer.com/Book.aspx?bid=632&title=Evinrude%2fJohnson+2-40+HP+Outboards+(Includes+Electric+Motors)%2c+1973-1990
But since you asked here is the down and dirty. First drain the lube, then remove the prop to facilitate putting unit in a vice later on to work on it. Shift into foward gear, you may have to turn the shaft a little. Remove the exhaust housing cover plate (plate with 2 screws about 5 inches up from the lower unit)to access the shift rod connector, disengae the shift rod. Remove the bolts that hold the lower unit on. Remove carefully. Thats the easy part. Make sure everything lines up when you put her together(water tube with pump grommet, drive shaft with crankshaft splines and shift rod with connector) Rotate the flywheel clockwise to let the drive shaft and crankshaft engage.[/url]

To ad to what fowlmood said, do not carry the unit by the shaft. If it comes unmeshed from the gears, you will have to completely disassemble the LU to repair.

On many of those motors, the powerhead has to be removed to get to the mounting bolts. We are going to have to do that to the '79 55 horse Johnson in the shop before we mount it astern the Lund. A good manual will lead you through both tasks, and it shouldn't take much more than your average tools.

Thanks for the replies. Can you guys tell by looking at where the oil is leaking what seal will need to be replaced? Is that a rediculous question?

We figured out our problem with the lower unit seal leak. Upon closer inspection, we found the bolts were loose as a goose. We were also able to get the upper motor mounts out and will replace them next week. Next we'll paint it and hopefully be done with it for at least this season...