Abu Ambassadeur

First of all you have to make sure that the reel has been set up correctly for your use. I you find that your always getting overuns then apply a little more brake until you get used to it.
Make sure the line is layed on the spool nice and evenly and use 15-18lb.Dont forget to always use a shock leader, they recommend 10lb for every oz of lead, so if using a 5oz lead you will need 50lb shock leader and so on.As you dont really know the service history of the reel it would be advisable to have the reel serviced, this will ensure that there are no underlying faults with the reel that you may not be aware of.One of the main reasons for overuns is the removal of the centrifugal brake blocks, make sure that they are ALL in place until you get used to the reel, and maybe then you might be able to get away with removing one. But to be honest they are there for a reason and by removing them will make the reel like a ferrari, if you cant handle it your loose control and experience overuns and major snapoffs quite often, also this could damage the the main spindle and ultimately render the reel useless.
High speed multiplier reels are precision pieces of equipment and should be looked after with great care, I always rinse mine in cold tap water after every session thats why they still look brand new even after many years.
Hope this advise is what your looking for.
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Tight Lines
Billy Townsend a.k.a townsendb46