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Question
3W Guru? Timing Question
OK, I'm trying to set the timing on a 3w200 twin; with the new 4 wire ignition. The local club experts have now confused me beyond belief. I am familiar with the C&H and RCExl ignition systems and the premise of 28 degrees before TDC. What is throwing me off is the two magnets in the hub and the verbiage in the manual. Basically what I need to know is where should the first magnet be in relation to the pickup when the engine is TDC?
Thanks for any help. |
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Approaching or departing edge? Please
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Bisection is the general activity of dividing a geometric figure into two equal parts. I agree with the pistons at TDC the hub and assoicated magnets won't be moving. But since we are discussing the physical placement of the pickup, which is movable, and the fact that it does have two edges; it is possible to bisect the magnet with either the approaching(right) or the departing(left) edge of the pickup. This would equate to roughly 5 degrees of timing difference which would surely make a difference in performance. |
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prop hub. If there is no problem with the prop hub slipping, when the two marks are lined up the pistons are at Top Dead Center. If the hub has slipped then you need a wire rod to insert into the spark plug hole and turn the hob/crank until the rod is push out to its farthest point. If you remove the timing sensor yourself hopefully you marked the bracket position so there should be no timing issue To set the timing call Gerhard at Aircraft International he will give you step by step instructions on how to put it back to were it belongs. I’m not an engine expert this is what I know from past experience. I hope this helps. Paul |
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Thanks Paul,
I actually talked with Gerhard earlier today and have to call him with info later. My problem is that a previous owner had attempted to put different ignition units on this engine. There are a total of 6 tapped holes where the sensor sits. Without knowing which two are the original, I have to know where the sensor sits in relation to the magnets. Hopefully Gerhard can help me straightened this mess out! Thanks again the reply. Rian |
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Good luck. Paul |
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It would have been easier with that information in the first post...
OK start oVer.. Check to see that the pistons are at TDC when the mark on the hub lines up with the mark on the case...If not the hub has slipped on the crank, take it off and do what it takes to fix it. Take the sensor off the engine..You will see a little steel pin on the underside..The ignition fires when the magnet passes the pin...Looking from the FRONT of the engine the sensor should use what ever threaded holes it takes to put the pin a few degrees to the left of the magnet..The edge of the bracket should Bisect the magnet under it...The engine wii fire a few degrees BEFORE TDC if the ignition is a 3W...It will ADVANCE when the throttle is opened... If the ignition is an RCEXL you can time it by following my instructions on Milton Thompsons rcextremepower website..PERIOD, end of post..... |
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