Re: Symptoms of bad "Power Pack" ?
yes, bad gas will make it run badly - before you start throwing parts at it, do this:
1. compression test - you want the lowest to be within 10% of the highest.
2. spark test - set your tester at 7/16" look for strong blue spark.
3. cylinder drop test - engine idling, pull then reconnect the spark plug leads, one at a time. if RPM's don't decrease noticeably, that cylinder's not making power. Use a spark plug boot tool to avoid electro-shock therapy, or ask someone you don't like very much to help out.
4. make sure the fuel line is holding pressure.
5. make sure the fuel tank vent is clear.
6. inspect fuel lines, look for old, stiff, cracking hoses.
7. listen closely for the sound of sucking air at all the fittings while someone pumps up the primer bulb.
report your results.