Chainsaws

My 2003 Poulan Pro 260 18" 42cc won't idle. It will run wide open but when I let go of the throttle it shuts down. Need to use the chock lever to get it running. I recently replaced the spark plug, cleaned the air filter, tried 2 different cans of gas thinking it was a fuel issue. The fuel lines look good as does the priming bulb. It was running fine for a while that morning, then started acting up. Not sure what to do, any recomendations would be appreciate. Thanks

Chainsaw will not start.
I have a new pp5020av chainsaw that ran for less than 1 tank of gas before quitting. Before quitting for the final time, it would quit after each cut when I would release the trigger. Before it quit for the final time, it would start right back up. It is running on new gas with the oil received in the case. The chain brake is not set and the chain moves freely. I cleaned the air filter, but that did not help. I let it sit overnight, but it still doesn't start using the quick start instructions.

I purchased a Poulan PRO PP4620AVX on August 6th, 2011. Within the first 15 minutes of use, the chain came off and whipped my leg. I had the chain properly tensioned when I started and had checked it within 5 minutes of the problem. Upon inspecting the bar knob,the lever on the bar knob was missing, lost in the grass somewhere. The base of the bar knob was there, just no lever to pull out and snap back in. The retailer does not service. I don't find a service center. I have a chain saw with 2/3 of the original tank of gas in it that is no longer functional. The whole chain tensioning system with the plastic adjusting wheel appears to be flimsy and non-durable. I wish I had inspected it closer prior to purchase, which then would not have happened. Needless to say, I did expect a useful life in excess of 15 minutes when I purchased the saw. Can anything be done, or have I just learned a painful lesson?

I have a poulan pro pp4218avx chainsaw that will only start when it's cold after about ten minutes of operation it won't start again. Why won't it start when it's warm could this have something to do with the points going bad effecting the spark or something?
P.S I'm pretty handy so can I order parts and repair myself?

Can you tell me the coresponding Oregon part numbers for the chains for the ES-350, model nr 952801954 (16" electric) and PLN1514, model nr 95202357 (14" electric) chainsaws (i.e. S49, S56, etc.)?