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Jeff G.
Jeff G., Marine Mechanic
Category: Boat
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Experience:  42 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance
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oil leaking out of lower unit on 1978 evinrude 70 hp do I need

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oil leaking out of lower unit on 1978 evinrude 70 hp do I need to replace lower seal kit and if so how to replace

Hello, and welcome to Justanswer. My name is XXXXX XXXXX I will be helping you today. If you need clarification on something please post back here.


Hi there,

Here is what I can tell you about this. First there is a small hiccup with your serial number. For a 78, the correct number should be 70EL73C, so something you might want to double check.


Johnson does not list a seal kit in the general catalog, you have to order it all individually. And there are 20 some odd seals and gaskets. Also, there are a few dealer only special tools that are involved with dissasembleling the lower unit to replace the seals. Without the tools, the job is next to impossible. If you boat in saltwater, the rear bearing carrier, which the propshaft seals are installed in, is going to be again next to impossible to remove, even with the special tools. And if you are to have to have any hope of getting it out, oxy-acetylene torches will be required.

This is not a job for the backyard mechanic. You do need a service manual to do this correctly. In all honesty I would contact an Evinrude dealer to see if they will take it in.


I know this is not the answer you were looking for, but it is the gods honest truth.


I would never ask a customer to hit accept unless they were satified with my answer. If you would like a second opinion from another expert, by all means just ask me an I will opt out of the question.


Best Regards,


Customer: replied 6 years ago.

Hi - Jason Let me start will the model # I rechecked it's the correct #. The boat is a 1984 Bass Tracker 3, I was told the engine was a 1978 so I 'am sure your right.


If I had the tools I think I can do this. I have been an auto tech for the past 30 years. But I understand your answer for most people but I think now I should have order a service manual for $ 32.00.



Hi Brian,

If you want to order the service manual. Really you want the factory one. The seloc's and Clymers are incomplete at best.

There is only 1 place where you can get the old OMC manuals, XXXXX XXXXX. He bought the publishing rights when OMC went out of business. Just google Ken Cool Johnson manual and you will get to the correct page to purchace the manual from.


About that model number. I made a mistake as well. For a 78 its going to be 70EL78C, with the last 2 digits being the model year. Your last to digits are 73. There is some confusion on this, so you might want to call a Johnson dealer because when I go into the electronic parts catalog this is what I get.


As you can see there is only the 1 70hp number. I think that you should get to the bottom of properly identifying what you have first before you even order a manual. And if you need help with that I certainly will try.




I just read my typo, I mean to say google "XXXXX XXXXX", not "ken Cool", lol!
Customer: replied 6 years ago.
Relist: Inaccurate answer.
He didn't how to look up the year of my motor with model
number and said the number I gave him was not correct. I went to and confirmed that it is a 1978 evinrude 70 hp. My model # XXXXX i need info on replacing seals in lower unit.He told me to take it to the dealer? I have over 30 years experience being an auto tech.
I will be happy to assist you. If you have a question or need clarification please post back at any time.
Yes, you have a 1978 70 hp Evinrude as you first stated.
The seal kit you want is part number 396349 although there may be a supercession to this number. You don't have to order the parts one at a time. You can also get the parts from a local NAPA store order part #18-2660.

To replace the seals you will need a puller that grabs the bearing carrier and pulls against the prop shaft. There are 4 machine screws that attach the bearing carrier to the retainer ring inside.
Other than that tool everything is normal hand tools.
You have two seals in the prop shaft bearing carrier, two under the water pump and the rest are O rings. Get some permatex Aviation Form a Gasket as well. Use it on the OD of the seals and O rings.
If you have any further questions on this let me know.
Jeff G., Marine Mechanic
Category: Boat
Satisfied Customers: 4724
Experience: 42 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance
Jeff G. and other Boat Specialists are ready to help you

I am going to word this as tastefully and neutrally as I can here, and if you would like a 3rd opinion i would gladly ask you to ask for one. But here is the story, and here is the source of the confusion.


For a 78 EVINRUDE 70hp the model # XXXXX XXXXX

For a 78 JOHNSHON 70hp the model # XXXXX XXXXX


They are the same exact engine, identicle in every way. The only difference in the market they were sold in in 1978.


The factory service manual is the same for both engines.


Part of this is my fault and I will accept some blame. My dealer software defaults to Johnson, and not evinrude, and I did not switch the tab over.



Both Johnson and Evinrude do not list a seal kit for this engine anymore.

If you want a seal kit from either Evinrude or Johnson (it won't matter), you have to order it seal by seal, gasket by gasket.

The part number listed above for the seal kit, 396349, is actually incorrect. There is a 0 in there. And it would be(NNN) NNN-NNNN But that is a moot point, because that part number has been discontinued a long long time ago. It is no longer available. It has not been superceded to any other part number.(at least that is what my software tells me, is that it is an obsolete part number).


If you want the factory seals from Johnson Envinrude, which was OMC, which is now BRP (confusing I know!) you have to order them seal by seal, no kits.

And this is going to get more confusing. the(NNN) NNN-NNNNnumber was a number that was carried by both Johnson and Evinrude, which at the time was owned by parent comapny called OMC. When OMC went out of business, and was purchased by BRP, BRP decided to not carry that seal kit any more. There is no Johnson, or Evinrude, or OMC as we know it anymore. There is only BRP. BRP still sells engines under the Evinrude name, but they are not the same engines. BRP decides what part numbers to keep, and which ones to get rid of, and that seal kit is one they got rid of. By all means please call a BRP dealer and ask them for the part number.


Now that other number above, 18-2660. That is not a Johnson Evinrude OMC BRP factory part. That is some aftermarket made in china companies part. I do not deal with that kind of stuff.

A good example is this, I have a Toyota Tundra. If you had a Tundra as well and asked me for the part number of the brake pads. I'm going to give you the Toyota part number. If there was not a part number available from Toyota, i'm not going to go get autozones, partsamerica, pepboys ect part numbers for all of the parts they claim to carry that may or may not actually fit and work.


I do aplogize if I was a source of confusion. These kinds of things happen when you deal with 30 year old engines made by companies that have been out of business for the last 15 years. But I do hope this settles some of that confusion.

And again I do apologize for getting Johnson and Evinrude backwards, but the rest of my answer was sound advice, and I do stand by it.


Post back with any questions.



396349 supersedes to(NNN) NNN-NNNNwhich was still being used on 2009 engines and is still available as a kit.

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