Snowmobile Repair: coil, ohm meter, propper

Question
I have a 1977 Polaris TX 340.
It has a very weak spark. How do I test the components to diagnose the actual problem, rather than spend a fortune in parts?
If I test the coil on a OHM meter, what result am I looking for?

Answer
Hello Greg,

  It sounds like you may have weak coils, if the spark is yellow, that is generally an indicator of faulty coils. Most coils don't last over 20 years. Make certain you're using the correct spark plugs, they are: NGK BR9ES, gapped at: 0.020. I would recomend starting with a fresh set of spark plugs, and checking to see if that helps first. I believe you have engine  model: EC34PT-05, wich is equiped with a CDI box, which is a failure prone part on these sleds, try removing it and taking it to your dealer. Most dealers will test the CDI for a reasonable price. As far as checking the coils with a OHM meter, the resistance varies to much to be accurate, and the propper testing equipment is very expensive, so I would recomed taking the coils to your dealer for a test too. Here are two websites that have good cheap parts: www.mfgsupply.com and www.denniskirk.com. Good Luck with the sled, and let me know if I can answer any other questions you might have.Mr. W