Johnson TS 20 Spark Issue
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Hi, All,
My Johnson TS 20 has no spark on the bottom cylinder, here is what I know so far. The plugs are good, I switched them between cylinders and have spark on top cylinder, the plug wires are old and they are soldered to the coils, both show continuity. The coils are not cracked and seem solid , when I Ohm them from the spark plug wire to either positive or negative lead the top coil shows OL and the bottom coil shows 7800 OHMs , but there is no spark on the bottom cylinder, testing the condensers on the bench both show OL and no gain in resistance, they should build some resistance slowly I believe. I have cleaned and adjusted the points and still have spark on top cylinder only. I realize that these coils, condenser and points are probably 75 years old , and from what I know about testing them ( that’s not much) that both condensers and one coil failed, the thing is the top cylinder with a failed coil and condenser has spark.
Any idea’s on what to do next.
Thanks
RJIf the condensers are old, most people consider them needing replaced,
and the test you did on them would not be adequate anyway from what
I know.The coils should be tested with the points and condenser “out of the circuit”,
or another words, disconnected.Did you take the points apart, dress and clean them?
If your plug wires are brittle or cracked, you may want to consider replacing
them as well, but at the least, check the continuity on the plug wires from the coil
to the terminal end to make sure all is well.Prepare to be boarded!
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Thanks Buc,
I cleaned and resurfaced the points , set @ .020 , put the condensers back in place, spun it over and now have spark on both cylinders, still unsure why the coils are reading OL on the top and 7800 Ohms on bottom, they were disconnected when I tested them, I should change the plug wires , they are the original screw on type. Just not sure if I’ll have to buy coils and condensers for the motor yet, I just started looking for them, was surprised to see that a coil cost $92 and a condenser $25, if I had to replace all of those at $250 not sure the motor is even close to being worth that, there are some other issues with it to , the shaft thrust washers are sloppy and its only is showing me 65 lbs. of compression.
But my thoughts were to get it running and see if the rings may come around after some run time and seafoam concoction TWC 3 oil mix.
RJRJ, the coils on these motors are usually good. I’m not sure why your getting a bad reading on the top cylinder, but the fact that it has spark probably means that the coil is OK. Are you testing the secondary from the upper coil wire all the way to the terminal? With the cracked wires, the continuity may depend on the position of the wire, and may come and go. Try testing from the upper coil wire to the soldered button where the wire connects. This will isolate the coil, and take the wire out of the equation.
If you determine that you have a bad coil, and it doesn’t sound as if you do, please don’t spend $92.00 on new old stock coils. There are lots of good used ones around. I see you’re a member, and “T” series motors are for sale at most of the meets that I go to for cheap money.
Here’s a website that may help. http://pochefamily.org/outboard/Coils.htm
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Aquasonic,
Thank you for the response, I tested the coils at the solder points and the wire ends with both connected to the points and condenser and with them disconnected from them, I got the same reading both ways, OL on the top coil and 7700 Ohm’s on the bottom coil. I cleaned and gaped the plugs to .030 and spun it over with a drill motor with the plugs grounded , very strong blue/ white spark on both plugs,
So I am not sure what to think, I am going to run it in the tank and see how it does and if the bottom cylinder drops out after warming up. Thanks for that link I saved it for future reference. I have been a gear head for years with most of my time spent on Hotrods and Harleys, still laughing about the day I stoped at that Estate Sale and 14 vintage outboards followed me home.
Steve“14 vintage outboards followed me home” Gotta love it! Talk about jumping in with both feet!
Blue/white spark on both cylinders sure sounds good. A run in the tank will be a good test. Let us know how you make out.
I wonder if it is possible that somebody put a TS-15 mag plate on your TS-20? TS-15 had maverick spark suppressors, TS-20 did not. It makes a big difference in how you test the coils. Connect your meter leads to the spark wire solder connection and the terminal of the ground wire at the armature plate, NOT to the plate itself. Connecting them correctly takes the spark suppressors out of the picture (if it has spark suppressors).
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Hi Frank,
I don’t think it a TS 15 plate, anyway I have tested the coils that way, the top coils shows OL and the bottom gives me 7700 Ohms. I had a good spark on both cylinders so I ran it in the tank and it stared fine but as it warmed up it would drop a cylinder under load, I am assuming it’s the top cylinder but with the screw on plug connector I can’t pull it off while running the motor. Once it drops a cylinder it runs not so good and most of the time dies. After it cools down it will start again and repeat the failure. This motor doesn’t have a lot of compression (65 ) so it’s never going to run real well unless the rings come around or I go into the power head and hone and put new rings in if that all it would need, any suggestions there would be appreciated.
So I think I’ll look for a used coil and start there .
RJRustedJunk place your screw driver on the spark plug nut and the metal of the motor at the same time.You will short the cylinder .
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