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Thought someone might find this interesting or amusing or possible both.
I had a magneto that would fail at high temperatures. Worked normal in cool weather. I have all LA-4 Eisemann's.
Replaced the coil, condenser, and points. I installed it with the second half of a ignition harness that I had bought some time back and only used one half of the set. New and previously unused.
The engine ran rough on that mag, dropping 100 rpm's but reliably constant.
Removed and played with mag several times and even installed a 3rd mag that I had gone thru pretty well. This is all on the "bottom" (left) mag. Same results every time. Replaced, rotated, plugs, ect. Everything kept coming back to the wiring harness even though I was trying to avoid that possibility (it was brand new, what the heck.) Finally Manufacturer said he would hi voltage test cables, did so, checked ok.
Mag(s) would produce a 5mm spark on the bench just by flipping them through by hand, even the one without a coupler. Would do it through the new wiring harness or straight off the coil.
Installed a new distributor cap and rotor. No change.
Now the fun part, just in the last 2 days. The plugs on top are non resistor NOS C-26's, installed in cans, and they run smooth on the other (right) mag. The ones on bottom are REM-40's full shielded resistor plugs as in the kind used everywhere. If I switch the left mag and harness that runs rough on the bottom REM-40's to the top plugs (26's), the engine will run smooth.
Conversely (or perversely) the smooth running mag and harness (right one) will run rough when hooked up to the REM-40's with them installed on top.
Those same REM-40's ran fine on the heat sensitive mag with the old wiring harness (when the weather was cool.) I have several spares plugs and rotating them in doesn't cure the roughness.
I have even made a fixture so I can couple the individual harness wire signals to an Oscilliscope and except for getting a flat line one time when oil got on a plug, it didn't show me anything grossly unusual. Did a bunch of other tests also.
ONE of the things I suspect is that there may be some problem in the area of the cigarettes on the plug ends of the cable. They are longer than optimum and not ceramic.
I have worked on ignition systems of all kinds since I was a kid, and this is the strangest problem I have ever seen.
Darryl
I had a magneto that would fail at high temperatures. Worked normal in cool weather. I have all LA-4 Eisemann's.
Replaced the coil, condenser, and points. I installed it with the second half of a ignition harness that I had bought some time back and only used one half of the set. New and previously unused.
The engine ran rough on that mag, dropping 100 rpm's but reliably constant.
Removed and played with mag several times and even installed a 3rd mag that I had gone thru pretty well. This is all on the "bottom" (left) mag. Same results every time. Replaced, rotated, plugs, ect. Everything kept coming back to the wiring harness even though I was trying to avoid that possibility (it was brand new, what the heck.) Finally Manufacturer said he would hi voltage test cables, did so, checked ok.
Mag(s) would produce a 5mm spark on the bench just by flipping them through by hand, even the one without a coupler. Would do it through the new wiring harness or straight off the coil.
Installed a new distributor cap and rotor. No change.
Now the fun part, just in the last 2 days. The plugs on top are non resistor NOS C-26's, installed in cans, and they run smooth on the other (right) mag. The ones on bottom are REM-40's full shielded resistor plugs as in the kind used everywhere. If I switch the left mag and harness that runs rough on the bottom REM-40's to the top plugs (26's), the engine will run smooth.
Conversely (or perversely) the smooth running mag and harness (right one) will run rough when hooked up to the REM-40's with them installed on top.
Those same REM-40's ran fine on the heat sensitive mag with the old wiring harness (when the weather was cool.) I have several spares plugs and rotating them in doesn't cure the roughness.
I have even made a fixture so I can couple the individual harness wire signals to an Oscilliscope and except for getting a flat line one time when oil got on a plug, it didn't show me anything grossly unusual. Did a bunch of other tests also.
ONE of the things I suspect is that there may be some problem in the area of the cigarettes on the plug ends of the cable. They are longer than optimum and not ceramic.
I have worked on ignition systems of all kinds since I was a kid, and this is the strangest problem I have ever seen.
Darryl
, they are too cheap to do the 500 hour service
. Maybe they dont think its necessary.... I have several customers that balked at it and I still sent out thier mags for the 500 hour and they always needed points and condensers as a minimun and the mags ran like new when i put them back on. Tim
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