yamaha boats
my 1998 yamaha 40 2stoke boat engine starts sputtering and slows down when i have it topped out after 5 minue?
after it shakes and seems to not fire correctly , i idle in gear for a min. and it goes away. What do i need to do?
first make sure the gas tank vent is open and clear.
then, make sure there’s no debris in the fuel tank, getting sucked up against the inlet screen then falling away when you shut it off.
next, when it starts acting up, start squeezing the primer bulb — if that makes it run better, replace or rebuild the fuel pump. If the bulb collapses (gets sucked flat), you have a restriction upstream of the bulb. usually a new fuel line including new primer bulb takes care of that. replace the quick-disconnect fittings while you’re at it.
if none of that helps, check for spark on both cylinders after it starts sputtering — I doubt it’s a spark problem but check it anyway.
At this point, you’ve pretty much ruled everything else out, so rebuild your carbs.
The 2009 Yamaha Boat Line