It could be one of 2 things - the pump has crud in it from the broken line,or the little passage has been blocked with crud from the broken line.You might be able to clear the oil passage by using a fine wire & feed it up in there,or you might be able to use something like PB Blaster to spray up in the oil passage too.If all else fails I think you'll have to pull the saw apart again & this time pull the flywheel to inspect the line that goes from the pump to the bar pad.I know how it is to pull a saw apart & think you've solved the problem fairly easily,but things can be disheartening at times.Too bad Mac (Jenn Feng) didn't use a better quality line.