Home › Forum › Ask A Member › 48 Sea King Spark Leakage – 2nd Update
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John Gragg.
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March 10, 2024 at 8:37 pm #285789
Hey All,
Still looking for ideas on what might have gone wrong on the magneto I built that was messing around with me. Frank sent me (in the original thread) some GREAT information loaded with “FACTS”. Cool stuff, I really enjoying hearing the real-real instead of the mandates we have all been taught as gospel.
Anyway. I took that mag plate off and built an entire separate one out of all NOS parts (with the exception of the coils) and two used coils I had in inventory. (I did NOT use the coils that were on the original mag plate).
I am now getting 5/16″ (or slightly better) spark from both cylinders. I also made sure both plug wires were always grounded to something. Either the spark tester or the crankcase via an installed plug.
If anyone has any ideas, no matter how crazy I would like to hear them. I’m really frustrated with this issue, as I really take my time when I’m building one of these magnetos and having one (possibly) fail really hurts.
Anyway –
Thanks to all for past and future advice. Much appreciated.
Best Regards,
John Gragg
RIverside, CAJust starting in the hobby, please be patient.
48 Sea King 5hp GG9014A
49 Sea King 5hp GG9014A
48 Johnson TD20
49 Johnson TD20
54 Johnson QD15
55 Johnson CD12March 10, 2024 at 9:53 pm #285793mercury used a sticky goop to insulate the coil wire connection. why not use the corona dope or liquid tape etc.
March 10, 2024 at 10:47 pm #285795mercury used a sticky goop to insulate the coil wire connection. why not use the corona dope or liquid tape etc.
I’m not against it (I’ve already ordered some), but being a little anal retentive and waaayyy too much of a perfectionist I’m trying to learn something and get it to work as intended.
Example: Is there a way to check the coils to see if they need burial services, because they show as good using the VOM. Apparently. If I read correctly, the coils might be cooked on the secondary side, but it might not show.
Appreciate the response!
Best Regards
John Gragg
RIverside, CAJust starting in the hobby, please be patient.
48 Sea King 5hp GG9014A
49 Sea King 5hp GG9014A
48 Johnson TD20
49 Johnson TD20
54 Johnson QD15
55 Johnson CD12March 10, 2024 at 11:42 pm #285797John,
First I’m not sure exactly whay your issue is . To check your coils using an ohm meter with nothing connected, what are your readings on the primary winding? put one lead on ground & the other on the points wire disconnected from the points, the secondary winding one lead of the meter on the spark plug terminal on the coil & ground the other meter lead on the K-ohm scale (1000) . Next check your capacitance on your capacitor. If it’s old it’s more than likely bad. Another timing check is your flywheel magnets have a north & south poles & your laminations or shoes have 3 points of contact. The magnets align with shoe A & B then align with B & C shoes. Exactly that point in rotation the magneto is producing the peak energy & the points should open at the time of rotation. I use a small lamp & battery to test as the flywheel must be on the crankshaft whth key in place, not tighted but placed correctly.Use a felt marker & straight edge to mark the magnet placement on the outside of the flywheel for clocking or placing the magnets in rotation.You can use an analog meter to test on ohms scale. Post results please. Also check the spark plug wire for any cracks or resistance in ohms scale. If bad replace.
March 11, 2024 at 2:02 am #285799John,
First I’m not sure exactly whay your issue is . To check your coils using an ohm meter with nothing connected, what are your readings on the primary winding? put one lead on ground & the other on the points wire disconnected from the points, the secondary winding one lead of the meter on the spark plug terminal on the coil & ground the other meter lead on the K-ohm scale (1000) . Next check your capacitance on your capacitor. If it’s old it’s more than likely bad. Another timing check is your flywheel magnets have a north & south poles & your laminations or shoes have 3 points of contact. The magnets align with shoe A & B then align with B & C shoes. Exactly that point in rotation the magneto is producing the peak energy & the points should open at the time of rotation. I use a small lamp & battery to test as the flywheel must be on the crankshaft whth key in place, not tighted but placed correctly.Use a felt marker & straight edge to mark the magnet placement on the outside of the flywheel for clocking or placing the magnets in rotation.You can use an analog meter to test on ohms scale. Post results please. Also check the spark plug wire for any cracks or resistance in ohms scale. If bad replace.
Hi Jeff,
Details in my previous post(s).
All the numbers were in line and well within tolerances.
Too much to write a 2nd time. Please take a look at the previous thread, I know you are very good with this stuff and respect your opinion greatly.
Best Regards
John Gragg
RIverside, CAJust starting in the hobby, please be patient.
48 Sea King 5hp GG9014A
49 Sea King 5hp GG9014A
48 Johnson TD20
49 Johnson TD20
54 Johnson QD15
55 Johnson CD12 -
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