New to the forum......hope someone reads this and helps with a solution.
While operating with my 6 yr old Stihl BR550 backpack blower, the motor suddenly stopped. There was no sputtering or coughing so I suspected an electrical rather than a carburetion problem. I removed the plug and grounded it out on the head but got no spark. Suspecting a bad plug, I used a spark tester inserted in the plug boot and grounded out on the head...still no spark. I removed the kill switch connection and cranked it using an electric drill to get up some speed with both the plug and tester...no spark with either. The gap between the flywheel and coil was 0.010". I cleaned off a little surface rust on the magnets and coil contacts but still no spark. The magnets were not discolored or damaged and both had strong magnetic pull.
After these tests, I felt the coil was bad. Neither of my local Stihl dealers had a coil in stock so I went on line and found a bunch of cheap Chinese coils with poor user reviews so I opted for a more expensive OEM model.
I mounted the coil when it arrived, making sure the insulating washers were installed properly between the new coil and head and the gap set correctly. The specs call for a gap between 0.006" and 0.012". I set it at 0.009" and the plug at 0.028". Cranked it up again using the drill and still no spark.
I removed the kill switch connector from the coil and again cranked it up...no spark. I ohm tested the ground wire and kill wire for continuity of the wires to the handle switch and found no breaks or shorts.
Please, can anybody help me with this no-spark problem? Unless the old coil and the new one are both bad, I can't think of anything else to do to get this blower firing.
Thanks for the help anyone can give me.
Glen
While operating with my 6 yr old Stihl BR550 backpack blower, the motor suddenly stopped. There was no sputtering or coughing so I suspected an electrical rather than a carburetion problem. I removed the plug and grounded it out on the head but got no spark. Suspecting a bad plug, I used a spark tester inserted in the plug boot and grounded out on the head...still no spark. I removed the kill switch connection and cranked it using an electric drill to get up some speed with both the plug and tester...no spark with either. The gap between the flywheel and coil was 0.010". I cleaned off a little surface rust on the magnets and coil contacts but still no spark. The magnets were not discolored or damaged and both had strong magnetic pull.
After these tests, I felt the coil was bad. Neither of my local Stihl dealers had a coil in stock so I went on line and found a bunch of cheap Chinese coils with poor user reviews so I opted for a more expensive OEM model.
I mounted the coil when it arrived, making sure the insulating washers were installed properly between the new coil and head and the gap set correctly. The specs call for a gap between 0.006" and 0.012". I set it at 0.009" and the plug at 0.028". Cranked it up again using the drill and still no spark.
I removed the kill switch connector from the coil and again cranked it up...no spark. I ohm tested the ground wire and kill wire for continuity of the wires to the handle switch and found no breaks or shorts.
Please, can anybody help me with this no-spark problem? Unless the old coil and the new one are both bad, I can't think of anything else to do to get this blower firing.
Thanks for the help anyone can give me.
Glen