abjay

Yes it did run well with the same battery and the battery charges well and hold a charge OK. You would think the battery is dead when you take it off the saw but it can still have over 18v left on it and powers drills and impacts just fine

First thing I checked, but the batteries work fine in the other tools, could it be that the batteries work ok in low drain tools like impact drivers, but can't deliver the amperage in high drain tools - is that possible?

Hi I have a makita 18v circular saw it used to work well but now it is so weak you can stop the blade between your thumb and finger, it starts up and runs fine until you put some load on it.I have stripped it down, the brushes are ok and make good contact, there is little or no sparking, the commutator looks good, I've checked the resistance between various points and everything reads ok. The tool has only done light work. Anyone got any ideas