Guest simon bourke Posted October 28, 2010 Share Posted October 28, 2010 hi gents... my 582 blue head, recently purchased, with 300 hrs, drops around 300 rpm when running on one of the circuits.ive put spanking new plugs in,gapped correctly, and its made no diff. now im wondering, where to from here? anyone know of a probable? should i just go kick the neighbours dog? Link to comment Share on other sites More sharing options...
Guest Crezzi Posted October 28, 2010 Share Posted October 28, 2010 IIRC the max drop on either single ignition is 300 rpm so you are within tolerance (just). What is the drop running on just the other ignition ? The 912 manual also quotes a max difference between the drop on each ignition but I don't think the 582 does. Cheers John Link to comment Share on other sites More sharing options...
JG3 Posted October 28, 2010 Share Posted October 28, 2010 Listen carefully and determine if the revs really do drop the at much on each ignition. For some unknown reason, sometimes the gauge shows more drop on one side than the other, but the true rev drop is the same. Something to do with wiring........ Link to comment Share on other sites More sharing options...
skeptic36 Posted October 28, 2010 Share Posted October 28, 2010 Hi people, The Rotax manual for the grey head states engine must be operated at 3000 to 3500 RPM ( it actually says 1/min not RPM) and the RPM drop must not exceed max 300 RPM (again it actually says 1/min) Regards Bill Link to comment Share on other sites More sharing options...
Guest 172M Posted October 29, 2010 Share Posted October 29, 2010 The two stroke rotax tach's are notoriously inacurate in the mag splits, If you have a prop tach it will give you the calculated actual drop. If not, and you know a R/C modeller they will have, or know some one that has a "blade pass tacho" and it is easy to calculate the engine RPM/blade RPM/ number of blades Cheers Link to comment Share on other sites More sharing options...
Guest simon bourke Posted October 29, 2010 Share Posted October 29, 2010 hi david... thanks for the reply.... umm, the rotax book says 300, so im close. the rev drop on the better circuit reads bout 30 or so, and there is a distinctive sound change on the weaker circuit. i dont think its merely a false reading. im thinking mabe i should head to a sparky and start to chase it properly. its one of the many things avionic that im learning that having people around who have been there done that, make it all make sense. like i dont lol.. thanks for bothering.. Link to comment Share on other sites More sharing options...
facthunter Posted October 30, 2010 Share Posted October 30, 2010 rev drop on 582. the spark plugs are not very far apart on the 582. Dual plugs give added safety ( redundancy) but they also have the effect of advancing the timing by lighting 2 fires instead of 1, in the combustion chamber, but the closeness of the plugs reduces the effect, in the case of the 582. but it's still there. IF you had one plug OUT when you went onto the particular magneto serving that plug you would get a hell of a drop as one cylinder would be completely out. What you are probably getting is a slight variation of the timing, due (I would say) to something to do with the CDI itself. The usual way to find out is to swap the unit with another and work by a process of elimination. You have to decide if this is worth the trouble and cost, depending on the type of flying you do. Nev Link to comment Share on other sites More sharing options...
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