'99 Johnson 70 hp - lower unit stuck - need help!

JPTL

Seaman
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Sep 20, 2003
Messages
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After disconnecting the shift rod under the cowling/carb & starter (what a pain), I removed the four 9/16-head bolts, the concealed single long bolt at the back of the section that's next to the tab - as well as the smaller, more recessed bolt next to it. That's 6 bolts in all, and a disconnected shift rod.
I can get the rearmost section to split about 1/8", but can't for the life of me get the front section to split enough to get a screwdriver in the gap to pry.
It's like I'm overlooking a bolt in the front somewhere.
What am I missing? Can it be that corroded in a guide pin?
Did it need to have been in neutral before disconnecting the shift rod and trying to split the sections? I know in order to drop the lower unit on an Alpha One, you need to be in neutral or reverse(?).
Is it just a matter of a corroded sleeve or guide pin, and if so, what are the tricks to break this corrosion free?
Thanks!
 

boobie

Supreme Mariner
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Re: '99 Johnson 70 hp - lower unit stuck - need help!

The drive shaft splines may be stuck in the crankshaft splines.
 

JPTL

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Re: '99 Johnson 70 hp - lower unit stuck - need help!

Would splines being stuck prevent even the slightest amount of separation of the sections? I can't even get them apart 1/16" in the center & toward the front. It's as if the two middle 9/16-head bolts were still in place and snug.

When you say stuck splines, stuck in the way of corrosion, or some other way? And if the splines are stuck, what would be a way to free them?
 

boobie

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Re: '99 Johnson 70 hp - lower unit stuck - need help!

Has this mtr been run in salt water ??
 

JPTL

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Re: '99 Johnson 70 hp - lower unit stuck - need help!

Yes. Mostly brackish. I just bought it and the seller suggested that it sat for a year or so before I bought it.
 

dazk14

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Re: '99 Johnson 70 hp - lower unit stuck - need help!

Post your model #.
 

JPTL

Seaman
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Re: '99 Johnson 70 hp - lower unit stuck - need help!

Thanks for the replies guys. Any help/suggestions are greatly appreciated.
Engine is a '99 2 stroke.
J70PLEEE

The engine runs fine, BTW. I decided it best to replace the impeller since the seller admitted that it hadn't been done in several years. Not sure it's moving water like it should however. If I can somehow confirm a stuck shaft, what about running it in a barrel with all bolts in but loose, and jamming it in and out of forward and reverse a few times?

I read on another forum, where identifying a 'married' shaft is discussed:

resecure the lower unit with atleast 1 bolt

gently pry the flywheel up and down to observe end play.
remove all lower unit bolts and have someone maintain a pry pressure downwards on the lower unit while you recheck for flywheel end play.
if end play is still there, lower unit stuck on something else.....shift shaft, other nuts and bolts etc....
if end play gone......driveshaft and crank are married....


It makes sense to me. The only thing is that I can't even get it pried apart enough to get a flat head screwdriver in there.
Thoughts?
 
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TD_Maker

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Aug 31, 2005
Messages
564
Re: '99 Johnson 70 hp - lower unit stuck - need help!

I was wondering if you got the bolt that runs through the Zinc Anode? I have heard of people loosening all the bolts, disconnecting the coils, and bumping the starter motor a few times in an attempt to knock it loose. Personally, I would whack it with a rubber mallet a few times to break the salt seal. Trust me, I live in Florida.....I understand .
 

dazk14

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Jul 22, 2008
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966
Re: '99 Johnson 70 hp - lower unit stuck - need help!

Can you rotate the gearcase relative to the exhaust housing?

Grasp the lower rear of the exhaust housing and grasp the rear of the gearcase and do a push/pull effect.

Do you see any movement?

If you intend to use wedges, make sure it has a broad width. A screw driver is not ideal. A wider wood chisel, construction flat bar are items you may have on hand. There are certainly many more ways to skin a cat.
 

phillnjack2

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Re: '99 Johnson 70 hp - lower unit stuck - need help!

if you find getting the shift linkage a pain to release your doing that wrong for starters.
releasing the shift rod is about the easist thing to do on a engine like yours, 30 seconds max.
only have to take off the R clip under the fuel primer and push the rod across to release from shift rod !!!!!!!
no need to remove any starter neither,that can stay completely untouched.
and no need to undo the carbs or the front of air box etc etc etc.

anyway back to your problem with the leg not dropping down.
go see how many bolts you have got off the lower unit, and let us know where exactly the bolts came from. as in
underneath the gearbox at the side, or the trim fin and the bolts underthere as well !!!

ive taken plenty of boxes off and not had problems,but also forgot to undo an extra bolt at different times and its had me puzzled
for a while.

if the drive shaft is stuck in the crank you have bigger problems to deal with.
for this i have no solution other than brute force and ignorance to get it off.



trying to pry the flywheel is a crazy idea, and if it does move you need a new set of seals maybe even a new block.
do not try prying the flywheel on these engines,its crazy and a very dangerous thing to do.
if the flywheel should develop a crack and go un-noticed it would make a mess at 5500 rpm when it breaks free !!!!!!!!
a 15 pound steel frisbee with teeth traveling at very high speed would be something i would try catching.

phill
 
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JPTL

Seaman
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Sep 20, 2003
Messages
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Re: '99 Johnson 70 hp - lower unit stuck - need help!

I was wondering if you got the bolt that runs through the Zinc Anode?
I didn't remove that bolt, as the zinc anode, it's bolt and housing are all part of the lower unit, and the bolt doesn't extend into the exhaust housing. Am I wrong about that?

Can you rotate the gearcase relative to the exhaust housing?
It will rotate, but only about 1/8" total. I tried to rotate it more to no avail.

if you find getting the shift linkage a pain to release your doing that wrong for starters.
releasing the shift rod is about the easist thing to do on a engine like yours, 30 seconds max.
only have to take off the R clip under the fuel primer and push the rod across to release from shift rod !!!!!!!
no need to remove any starter neither,that can stay completely untouched.
and no need to undo the carbs or the front of air box etc etc etc.
I got the instructions on how to release the shift rod from another thread somewhere. After going over my shoulder to get to my *****, I took a look at that R clip and how that shaft could slide and started to conclude what you say here. Oh well....


anyway back to your problem with the leg not dropping down.
go see how many bolts you have got off the lower unit, and let us know where exactly the bolts came from. as in
underneath the gearbox at the side, or the trim fin and the bolts underthere as well !!!
Here's a rough diagram of the bolts that I removed (red lines): Two bolts on either side of the unit 9/16" heads (four or these bolts); One large bolt forward of the circular fin plate (15mm head); and one smaller, more recessed bolt forward of the circular fin plate. So 6 bolts total.
Johnsondrawing.jpg

trying to pry the flywheel is a crazy idea, and if it does move you need a new set of seals maybe even a new block.
do not try prying the flywheel on these engines,its crazy and a very dangerous thing to do.
if the flywheel should develop a crack and go un-noticed it would make a mess at 5500 rpm when it breaks free !!!!!!!!
a 15 pound steel frisbee with teeth traveling at very high speed would be something i would try catching.

phill
I wasn't planning on prying the flywheel, simply checking for any up and down play with the lower unit snug against the exhaust housing; then checking to see if there's the same amount of play while prying the lower housing down/away from the exhaust housing. If there's less play, that would tell me that the driveshaft isn't sliding in the crank (splines stuck).
 
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pn

Petty Officer 1st Class
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Apr 20, 2013
Messages
374
Re: '99 Johnson 70 hp - lower unit stuck - need help!

well preventitive maintenance is one thing and enjoying your new motor is another. i say put her all together and enjoy the summer before it's gone. keep an eye on your tell tale/heat and take a look later maybe after some use something will shake loose. i've got the same issuse on a little tohatsu, running some salt away in a bucket every once in while. pees great though..
 

phillnjack2

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918
Re: '99 Johnson 70 hp - lower unit stuck - need help!

Now you ve started i would carry one and try to get the leg off and replace the impeller.
its ok for someone to say enjoy the motor, but being as you know its not been done for a long time is risking it big time.
2 minutes not cooling enough could destroy the motor to the point where even a rebuild kit is not going to fix it.
i would still think about another bolt somewhere that is not undone.
try taking the last little bolt out underneath,the one that holds the anode, you never know if someone has modified it in the past
and this could be the thing that lets it loose.
worth a try.
ill look at mine later as im surei have to take out 7 bolts to drop the gearbox.

worth a look
 
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