Air Conditioning - capacitor sizeing

Hey guys. I'm here in Las Vegas and guess what? yep. The scroll compressor hung on starting. Checked the relay contactor and the points looked burnt. Went to 2 different supply houses and only found one. A 2 pole instead of 1 and no jumper bar.
Hooked it up with a jumper wire added and it ran for a while OK. Then the pump sounded stressed again. This time I removed the jumper wire and moved the #1 lead directly to the same side as #1 & #2 taps. I noticed that the capacitor had a small burn mark on a lead. Its got a plastic housing so I could see about 1" of oil in the bottom of it. It's 2 1/2" dia by 3 3/4" long with 3 terminals. Question is: How do I match it ? Could this be causing the compressor motor to sound like it's not getting enough juice but still run? Any help is greatly appreciated. Thanks.

Replace the capacitor there should be markings on the outside like 35-5 370volts or maybe 30-7.5 440volts etc you can use a 35-5 440volts in place of a 35-5 370volts the higher voltage is ok but you must match the micorfarad ratings for your unit to function correctly. Do not use a 370volt capacitor in place of a 440volt one it will not hold up

I took the capacitor to 3 different supply houses, they couldn't tell me the size. One did check it and said it was OK but a contact looked risky. Anyway, got the size finally after an extensive web search of the unit. I don't think that's the problem though. Scroll pump starts, runs a bit then starts making an awful rattling sound. If I leave it alone, it will kick back in sometimes. Other times it sounds hung up. I can call a service tech out, but I would really like to get a handle on the problem first. The guys here in Las Vegas are a bit "iffy" if you get my drift. Thanks for your earlier reply.