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This page is about the repair of a Pulse Transformer ( P/N 610760 ) used in the under the flywheel Solid State Ignition
system of Tecumseh 1968 to 1973 cast iron, HH-100 , HH-120 and other engines. The other parts of this ignition system are
the Flywheel (P/N 610758) and Solid State Ignition ( P/N 610759 ) which are covered on other pages. You should be able
to click on an image to get a larger view.
December 05 / February 6 update;
On repairing several of these Pulse Transformers, I have found that
the open circuit is at the connection to the spark plug about one fourth of the time. Since this is the easiest to repair,
it should be the first thing checked. If the secondary circuit is open or resistance erratic, cut the boot off the terminal
that connects to the spark plug and measure the resistance between the stranded wire inside the spark plug wire and the mounting
bracket. If this reading is 2 to 5 K ohms, then replace the terminal with a Briggs and Stratton positive locking teminal 493880
or Stens 135-008, Figure A. Alternate part numbers are B&S boot, 66538 and Stens 135-081.
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| Figure A |
John Decker had two failed Pulse Transformers which he sent me to play
with. The initial testing of the transformer included measuring the resistance of the primary windings which was
.6 and .4 Ohms, (which is good) and of the secondary windings which were both open, (as in a broken wire).
The secondary winding should be about 2 to 8 K ohms.
I removed the black plastic outer layer from the first transformer and noticed
something dark in color embedded in the potting compound near the spark plug wire attachment point. I excavated some on the
potting compound around it and found the lead to the secondary winding. A resistance test showed 2.55 K ohms. Thus the brake
had to be somewhere in the spark plug wire.
 
The design of the repair was to maintain the strength of the mechanical connection, but separate the mechanical connection
from the electrical connection. To do this, I removed the old spark plug wire and replaced it with new copper spark plug wire
. This copper conductor was run thru the small nail hole in the nylon bracket and knotted about 1/2 inch from the end. This
provided a good mechanical connection for any pulling on the spark plug wire. The stranded copper wire continued on to make
the electrical connection to the secondary winding free of any mechanical stress.
When finished, I filled the cavity with E6000 adhesive.
When finished, I filled the cavity with E6000 adhesive.
If anyone wants me to repair another one, send me an email, edstoller@earthlink.net . The estimated cost is $ 25 as the
repair is time consuming.
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