I'm trying to ckeck the points on my 1970 40 h.p. johnson outboard, but i cannot get the flywheel to come off. I got the nut off but the flywheel will not move at all, even with a puller. I've tried to tap the bolt on the puller but that won't even do the job. I've even tried an impact wrench but i keep breaking bolts. I used a good penetrating oil but that wouldn't work either. Does the ice or dry ice, to get things cold really work?? I really don't want to use any heat, unless that ends up my final option. Any suggestions would be great. Thanks. 