Originally Posted by Stingraybob
Help. I have a 2003 240CR Stingray Cuddy Cabin with a Volvo Penta 5.7 GI engine. For some reason when ever we take it out and get it up to 30 mph the boat is fine but when w give it more gas it starts to backfire, chug and sometimes quit. We nurse it back to the marina. It starts right back up. I have replaced the distributor cap and router, and fuel separator. It gets a wine to it- my wife said it sounds like a dolphin crying. Does anyone have any idea what is wrong? I am so puzzled. We have NEVER had any problem with the engine before. I do all the maintenance on the boat. Some suggestions were maybe there is a slight crack in the gas line in the gas tank and when we accelerate it is getting too much air instead of gas. Has anyone ever heard of that being a problem? Please help.
Back firing is cause by what is called "Lean Burn" (lack of fuel). I had the same thing and it was the check ball in the top of the fuel tank was dirty. I suggest you check fuel filters and the check ball if it has one. The question is, does it do it all of the time or only when fuel level is down. There could be a pin hole in the stand pipe that will suck air when fuel level below the hole. Good Luck