Testing Coil on Elto Ace 4351-00687

[Murray Kahn]

All,

New member and first post! I just purchased this motor for my son and I to restore. I watched the Doug Penn Utube video on how to test a coil. My coil has continuity on both the primary and secondary circuits. However, my secondary circuit (the one to my spark plug) has 10.3 ohms of resistance instead of the 6 ohms that Doug said was correct for my coil. Is this coil any good? If not…anyone have a lead on where I can a good, working coil replacement?

Thanks in advance for any help that folks can offer….

Sincerely,

Murray in Seattle.

 

[Tom]

The secondary reading should be in kilohms (10,300 ohms).  If it’s really around 10 ohms, that’s a problem.

T

[crosbyman]

I am not familiar with those coil specs but… are we talking Kilo ohms here ??

what is happening with the coil … no sparks  ..weak sparks ?    condenser tested good with a high voltage leak test ?   point (s)  wiped cleaned  ?

 

from Boat House… years ago

Its pretty common for this magneto
to loose spark because of corrosion
in the point assembly. Disassemble
the points and clean everything and
recheck for spark. These coils are
rarely bad. I bet I have had 20 or
more motors with this magneto
that wouldn’t spark when I got them
but it was never the coil.

 

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The Boat House

[Murray Kahn]

Thanks Tom and Crosbyman…

I have not tested for spark. Just got the motor and opened it up to check that everything was there, connected and looked in good condition. Which is the case. Seemed easy enough to test for continuity while it was open.

I’ve got a fluke multi meter. its a fancy digital meter but it does not give me the scale in ohms….just a reading of 10.3.

Before I clean up the points can you share what i am doing wrong with my ohm test?

thanks

Murray in Seattle.

[crosbyman]

you must have a  small logo somewhere on the screen to differentiate ohms   kohms mgohms.

post the Fluke meter model # ….or check your user manual

 

why assume /worry the coil is bad..

 

condenser (s) are more lilely suspects .. they degrade over time     coils  unless  opn, cracked up or arcing to ground  will be fine.

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[joecb]

What crosbyman said …. the fact that you have continuity on both primary and secondary, and assuming that the 10.3  is in fact 10,300 ohms it’s very likely that with cleaning of the points and perhaps a new condenser you will have spark.

Joe B

PS, I’m an old guy, I like an analogue VOM, no confusion on “which scale” also enables the “needle jump” method of testing of condensers

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The Boat House

[Murray Kahn]

Thanks again you two….I will clean things up and check for spark and then get to you. I will also check my multi meter and post some photos of my motor as well as the ignition. Stay tuned!

Murray in Seattle.

[crosbyman]

Murray   here are some great articles on  capacitirors  guts, testing and repairs

https://wrcoutboards.org/wp-content/uploads/2020/04/Part1_Condenser_Construction_Failure_Modes.pdf

https://wrcoutboards.org/wp-content/uploads/2020/04/Part2_Condenser_Testers_And_Testing_Correctly.pdf

https://wrcoutboards.org/wp-content/uploads/2020/04/Part3_Sizing_Condensers_Correctly.pdf

https://wrcoutboards.org/wp-content/uploads/2020/04/Part4_Repairing_Broken_Condensers.pdf

 

small voms   analog or  digital meter with small internal batteries  (  3-9v usually) don’t have egough punch to test leakage  between  capacitor foils.

they may be fine for tesing OPEN or SHORTs  or  .uf values  but they are not effective to test HV leaks which will mess up ignition on OBs

as you read the   excellent articles  you will find that older OBs  need a bit bigger capacitors

 

if ever you wish to build a basic  capacitor tester….. here is a simple layout.  if the neon bulb  shines the capacitor is bad..simple!

Mr.Mohat offers alternatives …..also excellent but a bit    more elaborate.   I built  his basic model  #1 and it works wonderfully for testing caps.   Just write to him  for his design #1 schematic

 

 

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[joecb]

Capacitor tester … Somebody check me on this, but I believe that the tester crosbyman  attached the diagram for will indicate a good cap when the lamp DOES light. In fact, I have a tester that I believe is made as in the diagram and not only does the lamp light with a good cap, but it blinks at a frequency that is related to the rated capacitance of the capacitor. A smaller rated cap gives a faster blink rate, larger a slower rate. So that one can get a rough idea of the capacitance of a given cap by comparing the blink frequency to that of a known cap.

Joe B

[crosbyman]

interesting  conclusion    the way the rectified AC ….will load up the capacitor with rectified half cycles should also present those  half cycles to the neon lamp causing it to shine.     Internal leak in the capacitor  could  disrupt the shine  by shorting it out momentarily causing blinks as you indicated.

this woul be  oppposite to mr.Mohat ‘s test box where  the  caps are loaded  up  with about 275vdc by a voltage doubler  cct.   Any leaks  are picked up by the neon bulb  blinking or steady ON indicating a bad capacitor.

I have not built the  one in the attached drawing and would need to  to confirm it’s operation. I the mean time I’ll try to dig up  a circuit description for it to clear things up.

thanks for pointing it out.  IF anyone  has built one please feel free to comment.

 

 

upate:… not much luck finding a cct description & operation….anybody built one of these ???

 

 

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