Johnson TN28 coils

[bonzoscott]

I have scored a TN28 for next to nothing. It is missing the recoil but seems to have some compression. The coils are naturally trash. I have searched this site and someone recommended Sierra 18-5181 coils for this. When I looked into this motor, the coils have the plug wires attached and molded into the coil. When I checked out the Sierra coil, it does not have the wires. Does anyone have knowledge of this motor and where I need to look for decent coils?

 

[HighTrim]

Re: Johnson TN28 coils

All you need are the universal OMC coils, found just about anywhere.

The plug wire you buy seperately by the foot, you will need about roughly 6ft. It must be metal core, not automotive plug wire.

That TN will be a great learning experience for you. They are a little different from the norm per se.

The carbs are a little different, but once you get used to them they are no big deal.

You will need to fully read this to help with that motor. Any questions let me know.

http://www.pochefamily.org/outboard/

 

[1946Zephyr]

Re: Johnson TN28 coils

Yep, you got lucky there. TN-27 and 28's take the universal coil used in twins and singles from 1951 till 1976. points and condensors are the same way.

 

[bonzoscott]

Re: Johnson TN28 coils

Thanks fellows for the info. What I have trouble picturing is: The clearances are so tight in there, if you have to plug a wire onto the coil, where is the connection on the coil? Also, the nut for the flywheel on the crank is beat up a bit as far as threads, The crank is fine. Can I get that from Ace or do I need OEM? Thanks again for chiming in.

 

[HighTrim]

Re: Johnson TN28 coils

Take the whole mag plate apart and clean it. You TWIST the new plug wire into the coil BEFORE you screw it down to the mag plate. There will be a hole with a pin in it on the bottom/side of the coil that the new plug wires goes into. If you have never done an ignition before we can go into more detail for you if you like.

Those points look suspect from the pics as well, might want to get a tune up kit which will include new condensors and points.

 

[1946Zephyr]

Re: Johnson TN28 coils

The coil wire comes out under the magplate. When you take the three screws out of the coil to remove it, you'll see the spark plug lead. As bad off as your coils are, it's likely the spark plug lead connection will crumble, as soon as you lift the coil away.

As far as your flywheel nut goes, you may be best off to order a new one from Sea-Way Marine, but you can get a fine thread nut from the hardware store. Just make sure the nut is the same thickness, or it might rub on the starter assembly while it's running.

 

[bonzoscott]

Re: Johnson TN28 coils

Thanks 46 Zeph. I have disassembled and yes the wires crumbled off of the coils. That's what I don't get. If you have plug a boot in that same location at a right angle, looks like things are gonna rub. Would you recommend purchasing the coil from Shop2Evinrude or elsewhere?

 

[1946Zephyr]

Re: Johnson TN28 coils

They have them here at iBoats and also at your local marine supply. Any place that sells OMC parts will have the coils and tune up kits. HighTrim offered good tips to re-installing new wires to your coils. I would spray some WD-40 on the end of the lead and put it in, while twisting it. Also if there is a little rubber boot that goes into the magplate for the spark plug lead, then I would put that in first, then put the spark plug lead through it, from the top. The points can be cleaned up and re-used, if the contacts are not burned up. I would definately replace the condensors though. I have re-used a lot of point sets with good results. It's just the matter of how well they clean up. Some 400 grit sand paper on a flat surface will clean them up good. Like HighTrim said, just take the magplate assembly completely apart and clean it up really good and also remove the rings from the powerhead and clean and re-grease them too.

 

[bonzoscott]

Re: Johnson TN28 coils

Precise advise guys. Thank you very much! Points look pretty good. I will work on other vital signs. I have to get a couple of short nuts and lock up on the crank - use a drill and check compression.

 

[kfa4303]

Re: Johnson TN28 coils

Hi bonzo. This link should help too. It's for a different model than yours, but as the others have said, once you can work on one of these vintage OMC motors, you can pretty much work on them all. You should be able to get many of the parts you need to bring the motor back to life right here at iboats, just click on the "Marine Store" tab in the top left corner.


http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

http://www.duckworksmagazine.com/07/columns/max/index1.htm