I have a B&S 5.5 engine (103000 series) on a splitter that with the air cleaner OFF, starts & runs at max rpm (well I think it's max) for about 30 seconds, then slowly starts to lose rpm's until it stops. I can get it to run longer when I replace the air cleaner. However, I noticed the main jet adjustment has no effect whatsoever. I replaced plug, diaphram, cleaned carb and the breather thoroughly. When I finally get it running the engine doesn't seem to develop the HP as it will often slow considerably when I get into harder wood.

Charlie, January 2007

Will it start right back up after it dies, or does it have to cool down first?

Rick, January 2007

Thanks Rick, but I cleaned the screen when I removed the carb and made sure it was clear with compressed air. I cleaned the tank of some dirt too. And, I tried to see if the fuel cap was breathing, but I've never seen one like this before. Metal tabs hold it in place with a half-turn. There's no evidence of a pinhole to allow breathing. I tried to run the engine without the fuel cap to see if it made any difference and it did not matter - it still wanted to slow down and quit.

Charlie, January 2007

Remove the carb from the tank, and check for a clogged screen in the bottom of the fuel pick-up tubes.

Rick, January 2007