1973 johnson 6hp help

[junkyard5150]

Hi I am trying to get some help for my brothers 1973 johnson 6hp motor. The motor runs well but we just want to replace the impeller but after taking the four bolts off I can't seem to get lower unit to come off and i don't see where the shift rod would disconnect. He has the manual that came with it when he bought it last year but we can't tell where the disconect would be. so when we took the four bolts off the upper slides away from the lower about 1/4 inch or so and thats as far as it will go.
Thank You for your help.

 

[cr2k]

Re: 1973 johnson 6hp help

I cant remember which, there is either a small plate with 2 screws above the lower part of the leg, if not, shift in to gear (cant remember F or R) enough to drop the lower and you will see a double clamp that is the connector between the upper and lower shift shaft. 7/16 socket or flathead driver (use socket to avoid dropping screw). The bolt must be take all the way out as the shaft is cut to clear it.

When reinstalling the impeller housing use some silicone spray or dish soap to lube the impeller. Make sure you get the water tube plugged back into the housing. NEVER start dry, always use muffs or tank.

 

[F_R]

Re: 1973 johnson 6hp help

Stop!! There is a pin through the top of the drive shaft that has to come down through a slot.

1: Remove spark plugs and ground the wires
2: Shift to forward gear
3: With the four bolts removed, drop the gearcase as far as it will go. Then slowly rotate the flywheel. When the pin aligns with the slot, it will come down some more.
4: Now you should have enough room to get in there and remove a screw from the shift rod connector. 3/8" socket, 1/4' drive is best.
5: NOW you are ready to take the lower unit down and away.
6: Notice the position of the pin in the drive shaft so you can put it back in the same position for easy reassembly. Likewise, Do Not rotate the flywheel while the gearcase is off, for the same reason.

 

[junkyard5150]

Re: 1973 johnson 6hp help

Thank You for the quick reply. I'm gonna go over to his house today to help him with this. The water pump seems fine but why not get this done now. Its always better to know and do the maintinence than to deal with some problem out on the water.
Thank You and Merry Christmas

 

[1946Zephyr]

Re: 1973 johnson 6hp help

yea, I found out about that pin the hard way myself. I have a 74 Johny 6hp and on these, you don't have to remove the powerhead, like you do on the older engines.

 

[McGR]

Re: 1973 johnson 6hp help

I bought a nice little '68 6hp this last summer. When I rebuilt the waterpump I was oblivious to the "pin issue" with these motors. I don't recall having any specific issues removing or installing or l/u, though I might have rotated the flywheel during the process... don't exactly remember.

Anyway... this thread got me curious. So, I consulted the online parts diagram. Indeed, it does show the pin. It also shows items #1-6. I don't recall seeing these attached to the driveshaft. So - where are these located? Are they possibly installed in the powerhead? And what does the pin actually do?

 

[F_R]

Re: 1973 johnson 6hp help

I bought a nice little '68 6hp this last summer. When I rebuilt the waterpump I was oblivious to the "pin issue" with these motors. I don't recall having any specific issues removing or installing or l/u, though I might have rotated the flywheel during the process... don't exactly remember.

Anyway... this thread got me curious. So, I consulted the online parts diagram. Indeed, it does show the pin. It also shows items #1-6. I don't recall seeing these attached to the driveshaft. So - where are these located? Are they possibly installed in the powerhead? And what does the pin actually do?

A bit of history: Up until around 1964-ish or thereabouts, the seal parts were stacked on top of that pin and you had to remove the powerhead in order to remove the lower unit. If that were not so, the seal would all fall apart with no reliable way of getting it back together.

Then they put a ledge inside the housing to retain the seal parts, with that slot for the pin to come down through. That eliminated the falling apart when the shaft was removed.

Now in your case, if somebody forced it off without aligning the pin with the slot, they may have sheared the pin off. If that is the case, it is not supporting or rotating the seal parts. That seal is vitally important. If it is defective, incomplete, or otherwise leaks, it will admit just enough water into the crankcase to destroy the motor over time. Worst thing is, you don't know until it is too late.

Personally, I think the powerhead should be removed every time the shaft is pulled, whether it needs it or not--just to check the integrity of that seal. Maybe I'm over cautious, but my motors don't throw rods either.

 

[McGR]

Re: 1973 johnson 6hp help

FR - Thanks for the quick response. I do recall seeing the pin on the shaft. I remember wondering what the heck it was for. So, I don't think I sheared it off. I think I'll pull the l/u off (the proper way) to be sure the pin is still in good condition.