Saw acting up

[ALG]

Delta Shopmaster SS250 bought 5 weeks ago new in the box off Craigs list.
Saw just started this today. Speeds up slows down then quit. Started back up but would not run slow only fairly fast and quit again. I losened the on & off switch and blew in it and reattached it and the saw runs again at the higher speed. Any ideas on what is going on with it? I haven't tried changing the speed yet. You help is appreciated. 

[spirithorse]

I'd take the on/off switch off as you have already done and spray it with electrical contact cleaner.
After the cleaner has had a minute or two to evaporate, put the switch back on and go through the speeds trying to run it slow, medium and fast.
Good luck and God Bless! Spirithorse

[dirtrider73068]

You can go to radio shack and get a can of cleaner spray it will clean the variable speed switch or potentiometer knob its called , I am having this issue with my craftsman, turn it to a certain point and the saw jumps speed.