lower unit 6 hp johnson doesn't fit back together

[byronjacobson]

I have a mid 70's 6 hp johnson outboard. I removed the lower unit and installed a new impeller. Now I'm trying to reinstall the lower unit but can't get the lower unit to go back into place into the power head. It seems like the pin thru the shaft doesn't want to fit thru the slots at the top of the lower unit.
I've tried turning the propeller slowly and also tried turning the flywheel slowly but cannot get the lower unit to fit back into the power head.

I am spent about two hours trying different configurations and nothing is working. I've done similar jobs like this before but have never encountered a case where i couldn't get the lower unit back on again.

Do I have to remove the lower unit from the power head to see if the upper spring and seal might be out of alignment?
Please give me some good ideas to try before I throw the unit away.
thanks
you can also email me at jake331@charter.net

 

[F_R]

Re: lower unit 6 hp johnson doesn't fit back together

As I remember it, the pin has to be sideways (90 degrees from the fore/aft centerline of the gearcase). Then it can pass through the slot. However, the splines probably won't be aligned, since you have been turning the flywheel. So don't turn the drive shaft, once the pin is set as just described, but slowly rotate the flywheel till the splines will slip together.

OK, there is another possibility. The spring and/or seal parts may be broken and fallen out of place. In that case, it is of utmost importance that you pull the powerhead and fix the seal. Othewise, even if you do get it back together, the seal will not function and over time will destroy the powerhead. Hey, it isn't that bad a job. Remove the vertical throttle shaft, gas line, and 7 powerhead screws. Watch the screws, one or more of them may be longer than the rest. Reassemble the same position.

You will need a new powerhead gasket and whatever seal parts are bad. Always replace the 303347 o-ring and 303355 gasket (parts of the seal)

 

[byronjacobson]

Re: lower unit 6 hp johnson doesn't fit back together

Thanks for your suggestions. I will try it if I get time in the next few days. I notice the pin was pretty beat up so I even tried removing the pin to see if could get lower unit to slide back into place and I still had no success. I've been turning the prop and pulling on the starter rope but have had no luck. If your first suggestion doesn't work, i guess i'lll have to bite the bullet and take the power head apart from the lower unit. Any chance I will be able to reuse the gasket and not have to buy parts? also does that pin turn constantly and rub underneath the brass washer that holds the seal and spring in place? I would think it will wear out the brass washer in a short amount of time.

 

[Tim Frank]

Re: lower unit 6 hp johnson doesn't fit back together

Thanks for your suggestions. I will try it if I get time in the next few days. I notice the pin was pretty beat up so I even tried removing the pin to see if could get lower unit to slide back into place and I still had no success. I've been turning the prop and pulling on the starter rope but have had no luck. If your first suggestion doesn't work, i guess i'lll have to bite the bullet and take the power head apart from the lower unit. Any chance I will be able to reuse the gasket and not have to buy parts? also does that pin turn constantly and rub underneath the brass washer that holds the seal and spring in place? I would think it will wear out the brass washer in a short amount of time.

It is not clear whether you tried to remove the pin "and I still had no success." ....OR....you were able to remove the pin and THEN "still had no success."

 

[SeaKaye12]

Re: lower unit 6 hp johnson doesn't fit back together

also does that pin turn constantly and rub underneath the brass washer that holds the seal and spring in place? I would think it will wear out the brass washer in a short amount of time.

I have one of those 6 HP's too...and was wondering the same thing when I had mine apart. I guess I'll have to pull the powerhead next time just to see how that pin-seal assembly works. I can't envision how there would not be friction.

Guys that work in an active shop have such an advantage in that they see stuff dis-assembled all the time...and it makes sense much more easily than reading a manual.

Chuck

 

[byronjacobson]

Re: lower unit 6 hp johnson doesn't fit back together

hi again,

this morning i spent another hour trying to slide the lower unit back into place. I've removed the pin completely and even filed the end of the splines on the drive shaft hoping it would slide into place easier. NO luck at all.

Now i'm going to remove the power head and check out what's creating my obstacle. Hope this project goes better.

 

[raczekp1]

Re: lower unit 6 hp johnson doesn't fit back together

30 min to tear down powerhead,
but did you turn flywhell(crankshaft) when puting up lower unit?

 

[Tim Frank]

Re: lower unit 6 hp johnson doesn't fit back together

hi again,

this morning i spent another hour trying to slide the lower unit back into place. I've removed the pin completely and even filed the end of the splines on the drive shaft hoping it would slide into place easier. NO luck at all.

Now i'm going to remove the power head and check out what's creating my obstacle. Hope this project goes better.

How big is the gap at the lower unit~mid-housing joint? i.e. how close is it to fitting properly?
Is there any chance that the shift rod is causing a problem?
I think the shift lever needs to be in Reverse....or forward....one of the two.

Heck, my manual is on the shelf 3 feet away... just pulled out my manual to check....OK, from the relevant section, a few caveats...:

1)Is the gearcase itself in Reverse....and gear lever too? If you reconnected the shift linkage out of synch, I think that could cause your problem.
2) Could you have "over-lubed" the splined end of DS? This can cause a hydraulic lock.
3) Is the water tube properly located in the grommet? Same as 1)

Hopefully you have tried all of these before pulling the power head....but if you have done that already, i hope that turns out to have been necessary after all and is not one of these 3 items.....

 

[byronjacobson]

Re: lower unit 6 hp johnson doesn't fit back together

took the power head off the lower unit and discovered i was missing the spring 0303357 and lower washer 0303327 part numbers , the assembly that fits on the top of the lower unit shaft between the lower unit and the base of the power head.

I'm guessing one of the washers that was still in side the base of the power unit was blocking the splined shaft from fitting inside the powerhead.

Can't believe the bottom washer costs 15 dollars.

now i have to wait for parts to see if I can finish this job.

 

[F_R]

Re: lower unit 6 hp johnson doesn't fit back together

To answer one of your questions, the lower spring retainer washer has "bumps" on the bottom of it. The pin drives against the bumps, turning the washer. Friction turns the spring and carbon seal. The 303355 gasket keeps the plate from turning and seals it to the bottom of the powerhead. But you probably have already figured all that out.

 

[byronjacobson]

Re: lower unit 6 hp johnson doesn't fit back together

today i spent some more time trying to get the lower unit back onto my 6 hp johnson . I took an old 5.5 hp cd-10 seahorse johnson 1954 or so and took it apart to make use of the spring and lower washer I was missing on my 6 hp. this saved me about 30 dollars for the two parts plus i didn't have to wait for the items to be shipped. when i took lower unit off the 6 hp johnson and separated it from the power head, guess what i found in one of the cavities of the powerhead? Yes it was my missing spring and washer. Someone else or possibly me must had these pieces come loose when reassembling the lower unit. Anyway it was still a ***** to get back together but eventually I did.
I started the motor and was disappointed with how little water was being pumped. I'm pretty sure i put the impellar in correctly and also aligned the water tube. Maybe their is some blockage in the power head water jacket. Also the motor would only run for about 30 seconds and then it died. Any ideas what to check for to keep it running longer than 30 seconds. I did clean the carburator.

also one last thing, when putting the lower unit back together, the part with the 4 bolts down by the cavitation plate, i overtighened one of the 4 bolts and stripped the female threading. Without buying a helocoil kits, any suggestions on a simple way to fix that? Would a poor seal with the 4 bolts have caused the water pump not to work well due to a vacuum leak or something? This motor has really been a head ache for me. Wish I had not bought it. I've put a lot of time into it, although I guess that's how you learn,.

 

[tx1961whaler]

Re: lower unit 6 hp johnson doesn't fit back together

How high was the water in the barrel? It needs to be pretty high to pump well. It also just spits some water out of the exhaust relief hole, so don't expect a huge solid stream out of it. You could check the thermostat to make sure it is not clogged.

Does the motor keep running if you pump the primer bulb?