Re: spark question about 1983 75 hp 3 cyl
This is from Joe Reeves, who is very knowledgeable in this area, u may want to try this. Your compression sounds good so dont really need to worry about that.
(Continuity Of Magneto Coils)
Checking the continuity of the ignition coils....... Have the ohm meter set to High Ohms.
Remove the primary wire from points. Remove the coil ground wire. You do not want either of these wires touching anything.
Connect the black lead of a ohm meter to the spark plug boot terminal, then with the red ohm meter lead, touch the ground wire of the coil.
Then touch (still with the red lead) the primary wire. You should get a reading on both touches (contacts). If not, check the spring terminal inside the rubber boots of the spark plug wire.
If there is no continuity between the secondary circuit (spark plug) wire and the primary or ground, remove the coil from the armature plate, then check the continuity directly between the prong within the coil (prong that the plug wire connects to) and the primary and ground. Poor or no continuity of a coil (or plug wire) is one reason for weak spark, s/plug fouling, or no spark.
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(Magneto Coil Alignment)
(J. Reeves)
To align the coils properly, have the metal vertical portion of the coil yokes aligned with the inside edge of the bevel that exists on the top portion of the aluminum seat upon which the coils sit. This creates the proper distance between the coils and the flywheel magnets. Faulty alignment creats friction and the yokes of the coils heat up, turn blue and expand.
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(Point Setting Of Magneto Models)
(J. Reeves)
Set the points as follows. Have the flywheel key aligned with the fiber rubber portion of the ignition points. Adjust the gap so that a .020 gauge will pass thru but a .022 will not. Should there be any question of the points being dirty (touching the contact with your finger would cause them to be dirty), clean them with a small brush and acetone or lacquer thinner.
