I have a problem with my engine spitting, sputtering & backfiring when I get above 30 mph. I have changed the fuel pump and had the carb rebuilt. I put new plugs in. I checked the filters for trash and water and still doing the same thing.
Please post details of the boat/motor combo. What size engine,make(mercruiser, volvo-penta, etc), and size, and type of boat. That way we know what you are dealing with. Lots of great people on this forum, and they helped me with alot, and will help you also.
You could try performing a cylinder compression test to make sure the problem is not internal. The backfiring could be caused by ignition timing or possibly a sticky valve.
