Johnson Seahorse 5.5hp CD-12 restore

Apalie

Recruit
Joined
Jan 8, 2017
Messages
1
Some history
I got this CD-12 with the purchase of a new house. The motor probably sat for 10 years since the previous owner didn't seem to know anything about it and he had the house for 10 years. My son and I have been working to restore it since august. We have replaced all the gaskets, rebuilt the carburetor, converted from the pressure tank to the fuel pump, changed the impeller, changed the gear oil (which by the way looked and smelled like dog vomit). We have it running at throttle up.

Problems 1) The engine will not run at idle speed. We can get it running when it is set just above start on the throttle handle and then taken to high throttle right a way. It will run for a little while maybe a minute and then starts to bog down. And if you go towards idle or throttle down it will start to die. 2) It is extremely hard to pull start. I am 40 years old and in good shape and I have to pull with all my might multiple times before it will start. 3) There is a hole in the lower end above the prop that looks like it is supposed to be there. It is the size of a small nail maybe 1/16" diameter and leaks gear fluid when the engine is running and for a day afterwards. 4) The carb bowl needs a new gasket and filter. I have a solution for this from vintageoutboard.com.

In speaking with vintageoutboard he suggested there is something binding up either in the power head or in the lower unit. So I pulled the power head off and I can turn it easily. So my thought is it is in the lower unit. The shifter was in neutral and I was turning the drive shaft is very difficult. I expect there is a problem in the low end but I am unsure how to troubleshoot it. There is a lower end on sale on Ebay for $95 and I am wondering if I should buy that. The low end of this unit is pretty banged up. Any advice is appreciated. Thanks
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Check where you asked the same question on the other forum.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Very typical. Your shock absorber is sprung or broken. Sometimes you can put them in vice and press back together. If they are broken, you cannot. You CAN weld them if you get it real straight, but then you wont have any protection for your powerhead of course. They are still available used, PM me for details on this.

It is part #10 here in diagram. Below water pump. Johnson 5.5hp Gearcase.gif
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
I used to press those shocks back together, weld them and had no probs.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Forgot to mention the dimensions. Should be 6 11/16" long from end to end. Any longer and it will rub and bind, which is what you are experiencing.

As stated, you can weld them, but beware, if you hit anything such as a log or rock, you will destroy your motor. That shock is meant to take up the impact of a hit.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
How about a motor with just a straight drive shaft and no shock ??
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
How about a motor with just a straight drive shaft and no shock ??

Well they would have a prop with a hub to protect the motor right.

Racerone has a good point about using the brass shear pin, that would save her! Might want to keep a few spares on board however.

I have always had a stash of them, but I suppose at some point they will run out and ill have to start welding them as well.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
You may find that miotors with the shock absorber had a solid prop.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
You may find that miotors with the shock absorber had a solid prop.

Agree, that is what I was mentioning to Boobie. The reason that welding them COULD potentially be dangerous, if you don't have other means to protect your powerhead if you hit something submerged. A brass shear pin would help with that, OR if you could find a prop with a rubber hub? I don't know, never looked for that.
 

TN-25

Chief Petty Officer
Joined
May 27, 2008
Messages
607
How feasible would it be to run a 1966+ Johnson 6-hp lower unit with the splined propshaft and no shock absorber? The 66 models were redesigned to eliminate the shock absorber and replaced it with a splined propeller. The props purposely don't interchange with the earlier ones because you could potentially end up with neither the shock absorber nor the spline prop hub on a motor if they did.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
Yes you can fit a 6 hp lower onto the earlier motors.----Shift rod set-up needs to be changed as well.----The 66 models did not have a splined propeller !----They used a drive pin and rubber hub.----And the bearing surface above the pinion is too small on the post 65 models.----Seen many damaged there.---Other opinions will vary of course.----I think the lower units with the shock absorber are more durable.
 

BigB9k

Seaman Apprentice
Joined
May 24, 2016
Messages
48
I personally would put a 6 HP lower on it.
As mentioned, you'll have to swap shift rods, but no big deal.

The advantage is you'll have a larger selection or props available to you, and have a more modern prop nut.
 
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