I had a Brison 2.4 with exactly the same problem. After many, many frustrating days at the field and 2 trips to Brison ( very expensive ) I sent it to C & H ignition. He told me I had a weak coil in the ignition unit and that coupled with the fact that Brison's have waaaaay too much gap on the pick up was my problem. They installed a new ignition unit, closed the gap on the pick up by at least 50% and it now works great. Starts very easy hot, cold or anything in between. If all else fails give them a try.