Postby IAN TURNEY-WHITE » April 21st, 2021, 3:24 pm
The Becker ignition units are designed to work on 4 cell nicads or nimb batteries or via a regulator set to no more than 5.5 volts
Two types , early units had advance/retard via the sensing magnet being on a spring loaded arm inside the hollow rear part of the prop hub , advance operates thru centrifugal force .
The later types have electronic advance and retard and the magnet is fixed in the outside rim of the prop hub
The bracket that holds the sensor above the magnet has slotted screw holes and small adjustments can be made .
You need a gap between the magnet and sensor approx 0.6 to 0.8 mm
The timing is correct when slowly turning over the motor , the spark plug " sparks" at top dead centre , the magnet just starting to
go under the sensor. Do not energise the ignition unit without spark plugs being fitted
Care needs to be taken with regard to the plug caps ,these are best removed if required , when the caps and plug caps are not hot/ cooled down ,and care needs to be taken not to pull on the ht lead .
Looking inside the plug cap you should see a small brass "pip " which provides electrical contact to the aluminium threaded sleeve on the end of the spark plug
Early plug cap internals ( black ) could sometimes melt and removal of the plug cap could then be a problem , maybe arranging for air cooling to the caps would be useful
Later plug cap internals seem to be made from a more heat resistant ( white ) material
Hope the above helps , regards Ian Turney-White
