1984 Johnson 15 lower unit water tube removal

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Tubs
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1984 Johnson 15 lower unit water tube removal

Postby Tubs » Fri Jul 13, 2018 11:45 am

A friend has a long shaft and a short.
Short shaft works on his boat but has issues.
Long shaft has almost no hours but doesn't
work on his boat. Removing the extension.
He is as far as the water tube. How does
that come out? Do you have to remove the
power head?


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rjoynt
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Re: 1984 Johnson 15 lower unit water tube removal

Postby rjoynt » Fri Jul 13, 2018 11:50 am

Tubs, I don’t know the answer, but I have found http://www.leeroysramblings.com/Outboar ... icles.html

Leeroys to be a great website to read.
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Bob Joynt
Secretary/Treasurer
Western Reserve Chapter - Ohio

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Fisherman6
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Re: 1984 Johnson 15 lower unit water tube removal

Postby Fisherman6 » Fri Jul 13, 2018 12:20 pm

Tubs,
I believe the powerhead has to come off to chage the water tube. If memory serves me the water tube is captured by the inner exhaust tube which is fastened to the bottom of the powerhead independent of the midsection. Exhaust tube and water tube will come out with the powerhead. The exhaust tube must then be removed on the bench to swap out the water tube. Someone will correct me if I'm wrong.
-Ben
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Tubs
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Re: 1984 Johnson 15 lower unit water tube removal

Postby Tubs » Fri Jul 13, 2018 2:51 pm

Thanks Ben.
Relayed your information and he is very
grateful. He’s and old codger like me and
he’ll get around to it when he gets around
to it. If I remember correctly he said he had
to leave the lake tomorrow for a few days
so it may be a bit. I know he will get it done
though.
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fleetwin
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Re: 1984 Johnson 15 lower unit water tube removal

Postby fleetwin » Fri Jul 13, 2018 7:01 pm

Yes, the powerhead must come off if you want to remove the water tube...
But, is he trying to make a short shaft engine out of a longshaft? I suppose it is possible to cut 5" off the water tube without removing the water tube, but it will be tough to get a cutting tool up inside the exhaust housing....
If you decide to pull the powerhead, know that this engine has the troublesome water tube grommet set up, and this engine may have two water tubes if it is a 15hp. The shorter tube just directs the cooling water down inside the rear passage of the exhaust housing and away from the open exhaust megaphone.
This engine looks like it is a fresh water engine so crushed water tube grommets is probably not an issue. But, your pal will want to update the water tubes and grommets if he is going through all the trouble of pulling the powerhead. There is also another way of avoiding future grommet issues by installing the grommets "improperly" on the original style water tubes. Let me know if you need/want more info...Don

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Tubs
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Re: 1984 Johnson 15 lower unit water tube removal

Postby Tubs » Fri Jul 13, 2018 8:01 pm

Thanks' Don for responding. All he wants is
to make it a short so he can use it. The
design is making that more difficult than it
could be. Probably not a big deal for you
guys who fed your family fixing these things
but I find them to be a pain and have no
interest in working on them. He has already
determined that cutting off the tube would
be the easiest but not possible with the tools
he has here because of its location. You could
probably do it with a worn down cut off wheel
but no tool, no air. I’ll catch him tomorrow
before he leaves and share what you have
posted. Thanks again for your incite.
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Dan in TN
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Re: 1984 Johnson 15 lower unit water tube removal

Postby Dan in TN » Fri Jul 13, 2018 8:12 pm

I have one of these (even smaller) that I use. Can't find a picture at the moment. Mine won't cut a 7/8" pipe. Even leaves the copper tube rolled in on the end. Perfect for going into the water pump housing. Might save you a lot of time since it is a fresh water motor.


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image.jpeg (16.44 KiB) Viewed 182 times




Available at Autozone for $8.99, but you can get all types from Amazon to eBay.


Dan in TN


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Tubs
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Re: 1984 Johnson 15 lower unit water tube removal

Postby Tubs » Fri Jul 13, 2018 8:35 pm

Thanks Dan but not enough room.
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fleetwin
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Re: 1984 Johnson 15 lower unit water tube removal

Postby fleetwin » Sat Jul 14, 2018 9:30 am

Tubs wrote: Thanks' Don for responding. All he wants is
to make it a short so he can use it. The
design is making that more difficult than it
could be. Probably not a big deal for you
guys who fed your family fixing these things
but I find them to be a pain and have no
interest in working on them. He has already
determined that cutting off the tube would
be the easiest but not possible with the tools
he has here because of its location. You could
probably do it with a worn down cut off wheel
but no tool, no air. I’ll catch him tomorrow
before he leaves and share what you have
posted. Thanks again for your incite.


I hear ya buddy. I can understand why your buddy does not want to get so involved with this project. So, I am sure, that between the two of you, you can come up with a way to cut 5" off that water tube to avoid pulling the powerhead. Like I said, this looks to be a fresh water engine, so I'm sure crushed water tube grommets are not an issue....

Dougs Outboards
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Re: 1984 Johnson 15 lower unit water tube removal

Postby Dougs Outboards » Sat Jul 14, 2018 10:58 am

I would simply use a dremel and a small 3/4" - 1" abraisive cut off wheel. If I remember right, there would be plenty of room to cut it off up in there, it's up in there inside the leg about only a couple of inches I guess, (the cut off point I mean). There's only about 1" of the water tube sticks down below the hole in the casting at the bottom of the leg on a short shaft, (and the rubber grommet butts up to the bottom of the casting when installed) and, easy to get at, from my memory anyway. Maybe someone here has a short shaft motor with the lower unit already off and can measure the short length of the water tube protruding down from the casting inside the leg and can report here on the forum. (pugetsoundboater possibly?) then problem solved. And I am sure you can find an easy way to smooth the burrs left on the edge from cutting that water tube off, (small file, very small diameter round grinding wheel in the dremel, etc).

And I agree with Tubs, I always found them a pain to work on too, but very good motors they are... Very powerful, and great sellers in my area.


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