I had a 95 Formula S 380. It was a great runner. I would check the carbs first. Take them off and clean them. Pretty easy to do on that machine. Next I would look at the fuel lines. It's pretty old now and if there are any air bubbles in the line look for a air leak somewhere at a fitting or even in the tank (just fixed my 80 340 7500 Plus line in the tank a week ago as it had fallen off). Just check the simple stuff first.