# 1978 Johnson 35 hp Lower Unit



## DiveLiberty (May 6, 2018)

Well, I've had a string of bad luck on outboards. 

I purchased a 1978 Johnson 35 hp motor last month. It starts up great and shifted well on the muffs. However, when I took it out on the lake, it slips out of gear at about 15 mph or so. It feels like I'm hitting a stump. I believe the issue to be a clutch dog. It seems like that was a real issue with this model of lower unit. 

After doing some research, I'm not quite confident enough to get in to the lower unit to change the clutch dog. The bearing housing pull intimidates me a bit and I'm most worried about getting everything back together. Additionally, it looks like a new gear set runs about $300. My thought is, at that price it would be easier and not too much more money to find a used lower unit. BUT, I've scoured the interwebs and haven't found a single compatible lower unit. 

Three questions:

1. Honestly, how difficult is it to get into the lu and change the clutch dog? I'm decently mechanically inclined, and don't mind doing most of my own work.
2. Does anybody happen to have a working LU for this motor sitting around?
3. Does anybody have a secret source for used LU's that I haven't found? 

Thanks guys!


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## hardwatergrampa (May 6, 2018)

do you have a picture of the motor I think I had 1 with a bad head


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## DiveLiberty (May 6, 2018)

hardwatergrampa said:


> do you have a picture of the motor I think I had 1 with a bad head



Sure thing, here is a pic.







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## hardwatergrampa (May 6, 2018)

mine was a evinrude long shaft ill try to check to see if I still have it this week is yours long or short


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## DiveLiberty (May 6, 2018)

That would be great, I appreciate it. 

This one is a long shaft, so that would likely work. 


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## Pappy (May 6, 2018)

Post the model number of your engine.


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## DiveLiberty (May 6, 2018)

Pappy said:


> Post the model number of your engine.



Thanks, will do when I get home. 

Off the top of my head, model 35EL78R. Will update for sure when I get home. 


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## Pappy (May 6, 2018)

If so that would indeed be a 1978 electric longshaft. Take a good look at the powerhead and see if that engine looks like it has been overheated at all. Reason I ask is that in the 1978 vintage there is a plastic water tube coupler about half way up in the exhaust housing that melts and will NOT seal properly again. That part has been obsolete for quite a number of years as well. Was a kind of an Achilles heel for that engine and that design as well as internal and external lower unit designs changes rapidly. From around 1982 on up that engine and gearcase was pretty much bulletproof.


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## DiveLiberty (May 6, 2018)

Figures I found one of the only bad Johnson’s out there. [emoji849]

The powerhead seems to be in great shape. The block is very clean, no flaking paint or anything. It pumps water pretty strong as well. It seems to run well excepting the lower unit issues. 

Thanks for the heads up though, I’ll be sure to keep an eye out for that issue. 

A guy has to fish, so to this point I’ve just been idling around the lake to my spots. 


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## Pappy (May 6, 2018)

If it has not been overheated and that coupler melted then you still have a good engine. Did not mean to be misleading. The powerheads were and still are pretty much bulletproof. When the gearcase issue is resolved please note that there is a shift adjustment at the base of your shift handle on the side of the engine that can help you from having that issue again.


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## donairplane (May 7, 2018)

What is the fix for that obsolete water tube coupler if it is melted?


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## Pappy (May 7, 2018)

Have not looked for a fix. Usually not worth it as the powerhead/inner exhaust has to come off to get to it.


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## donairplane (May 7, 2018)

Thanks for the reply.


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## hardwatergrampa (May 8, 2018)

haven't had time will try in the morning and seeif I can get model no. this motor did over heat


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## hardwatergrampa (May 9, 2018)

maybe some 1 can tell if it will fit ser #j30elcrr mod # is e600 4748 have pictures on my phone but don't know how to post them ill have the grandson do it this weekend


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## nccatfisher (May 9, 2018)

hardwatergrampa said:


> maybe some 1 can tell if it will fit ser #j30elcrr mod # is e600 4748 have pictures on my phone but don't know how to post them ill have the grandson do it this weekend


If you want to send the pics to 704 223 4637 I will post them for you.


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## Rocs (May 17, 2018)

I have replaced the dog on a '78 15 horse and the gear set on a '92 30 horse (Johnsons). Takes about a dozen cuss words is all.


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## DiveLiberty (May 17, 2018)

@Rocs my biggest issue at this point is cost. I’ve read a few places that if the clutch dog is bad, chances are that the gears are as well. A new gear set is about $300. At that price I’ll be looking at new motors! I only paid $400 for this motor to begin with. 


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## nccatfisher (May 18, 2018)

DiveLiberty said:


> @Rocs my biggest issue at this point is cost. I’ve read a few places that if the clutch dog is bad, chances are that the gears are as well. A new gear set is about $300. At that price I’ll be looking at new motors! I only paid $400 for this motor to begin with.
> 
> 
> Sent from my iPhone using Tapatalk


And many times you are correct. But you paid $400 for a motor with issues. I don't know about Mo. but around here you won't get a known good motor that size for $400. or no where near it. You would be looking at a couple thousand. Sometimes it is better to go ahead and fix what you have.


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## Pappy (May 18, 2018)

Count on the gear being as damaged as the clutch dog is. 
Now, how the gearsets are handled. If you need a fwd. gear (and you do) it is sold along with the pinion gear as a set. 
The reverse gear can be left alone as it is probably okay. 
If you go that route remember what I told you early on about the adjustment on the gear handle. When shifted the unit has to be all the way in gear.
This can be felt as additional resistance when the clutch dog lug bottoms out in the gear.


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## DiveLiberty (May 22, 2018)

nccatfisher said:


> DiveLiberty said:
> 
> 
> > @Rocs my biggest issue at this point is cost. I’ve read a few places that if the clutch dog is bad, chances are that the gears are as well. A new gear set is about $300. At that price I’ll be looking at new motors! I only paid $400 for this motor to begin with.
> ...



That's a great point, and I'm glad you brought it up. Even if I have to put another $400 into this thing, I'll have a running and working 35hp for $800. That's still a pretty good deal.


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## nccatfisher (May 22, 2018)

If it runs well, or I felt confident with the motor that is exactly how I would look at it. Buying a used one is always somewhat of a crap shoot even being as careful and as prudent as you can. If your top end is known good I would repair the LU and feel confident I had a good unit still considerably cheaper than normal market value.


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