1997 15 hp hesitation

[bubba9915]

I have a 1997 Mercury 15 hp 2 stroke that falls flat on its face on acceleration after running at a slower speed. I am at altitude of 5135 feet. I changed the main jet from .072 to .068. the float is set at 1 inch. the gaskets on the fuel pump look new. the person before me might have rebuilt carb. Initial timing is at 8 btdc and goes to 36 btdc at wide open throttle. It seems like it is starving for fuel. thanks

 

[johnnygjr]

try priming bulb while running,it will act as a fuel pump.

 

[bubba9915]

that did not make any difference, have put clear plastic tube where the fuel filter goes and see fuel with no air bubbles. when I sprayed carb cleaner into carb when this
was happening the rpms came back up

 

[johnnygjr]

Somethings not right here, primer bulb does nothing but carb cleaner increases rpms. check your float level function and needle and seat for possible obstruction

 

[galamb]

Yes, perhaps a clogged main jet or clogged float valve - if putting fuel "down the throat" cures the problem that indicates that not enough fuel is getting to the throat under normal operation.

If the previous owner did "not" rebuild the carb then a good cleaning and possible rebuild may be on the "to do" list...