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Clooney
05-11-2002 16:34:26
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Re: How do you time a 48 D? in reply to Kirk in PA, 05-11-2002 15:38:55
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Kirk, you didn't say what model Wico mag you have but I will assume it is a Wico X or C, probably an X.
~When checking with a timing light & the engine is running over 250 RPM [basically running] the L/H plug should fire about 30-35* before the L/H impulse mark lines up with the case mark.
~The Wico X, H, XH all operate about the same way...When installed & over appx. 250 RPM the mag basically sparks at around 25-35* before TDC [ or 25-30* before the L/H impulse mark], depending on the mag lag setting & mag type. ~There is an adjustable stop ring on the back of the mag that has a stop on it that catches little [trip] arms sticking out of the impulse cup. At speeds under appx. 250 RPM the trip arms stick out & catch on the stop ring stop & allow a spring in the impulse cup to wind up while the [flywheel] crankshaft keeps turning, when the [flywheel] crankshaft gets to TDC [L/H impulse mark] the stop lets go & allows the mag to [snap] forward & make a spark [therefore the mag actually sparks at TDC [L/H impulse] at cranking speeds--under 250 RPM-].
~ After the engine speed reaches 250 or so RPM the trip arms retract due to centrifugal force & the mag reverts to base timing which is actually where the mag is installed at.
~The running timing on a late "D" is around 35* for kerosene with standard compression. I have found that my personal "D's" run good at around 30* BTDC timing when set with a timing light.
~To set a "D" or most hand start 2-cylinder Deere's with a timing light....use a tape measure & measure the circumference of the flywheel, then divide that number by 360, that will give you the inches per degree, then multiply that number by 30 & that will give you the total inches for 30 degrees, then measure that distance in the advanced direction from the L/H impulse mark on the flywheel & put a paint mark. All you have to do then is run the engine at high idle & shine the timing light on the flywheel & see if it flashes when the paint mark lines up with the case mark. The mag can be loosened & turned to get the paint mark to line up. Once the running timing is set (a Wico X & C has no mechanical advance), stop the engine & slowly roll the flywheel in the running direction & see if the mag snaps when the L/H impulse on the flywheel lines up with the case mark, if it doesn't, the stop ring is set incorrectly or the impulse is worn. ~If after the running timing is set & you find that the mag doesn't snap at L/H impulse to case mark while cranking, post back or E-Mail & I will tell you how to set the impulse stop as it depends on the impulse cup.....
~Points, plugs & condenser can be bought from Deere, some autoparts stores, or John R. Brillman (610-252-9828) 6-10 pm est. Roberts Carb (712) 262-5311) has the parts also.....
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