Hi Grumpy, have done as you suggested. Took spark plug lead off, still wont start on compression stroke, any were else it will. Carefully watched rocker arms while rotating the motor, slowly through compression stroke, no movement at all. Done it a couple of time just to be sure. If it is the decompressor that is no good how could that be causing the "backfire" (am i getting to ahead of things at the moment).
