My mechanic says I need to rebuild the carbs on my 67 100 hp (model vtl13a). He says the kit alone is $250.. I am looking for alternatives, assuming I do need to rebuild it. Is this a legit price, anywhere to get it cheaper? Can I do this myself? It would need to be fairly simple. The motor ran pretty well last fall, but now it backfires and wont start. I did not stabil the fuel. I did not run the motor out of fuel before storage.