Yamaha F30BEHTL 2011 - sputtered, wouldn't start, 4 stroke EFI - fuel problem

[TheBelvedere]

Hi folks,

thanks for operating such a great resource.

My four stroke 30 has around 50hrs and is well looked after. The other day it was working fine and then just wouldn't start at all.

We have changed - plugs, interchanged a non-genuine 10micron low pressure fuel filter and replaced all external tank fittings & hose.

We bled the fuel system from the vapour separator, and the fuel that comes out is bubbly, like soda water. Once we have emptied it, the motor is primed and starts ok, runs ok, then either gets rough and stalls or will stall under throttle.

Repeat the fuel bleed from vapour separator and the fuel is bubbly again. Is this normal or is air getting in somewhere?

The only thing I haven't replaced is the fuel tank itself.

Is this likely a leak in-line or could the fuel pump cause this behaviour? Could vacuum lock cause or initiate these issues also?

Thank you so much. Motor is my baby... Been tinkering since Thursday as my dealer is doing the 'dirty fuel' thing and seems to think I might have to pay him for my time.

 

[99yam40]

Re: Yamaha F30BEHTL 2011 - sputtered, wouldn't start, 4 stroke EFI - fuel problem

hook up a portable tank with fresh fuel, flush all lines and filters of old fuel, the whole system.
Fuel should not be bubbly like soda water, it must be contaminated with something

 

[TheBelvedere]

Re: Yamaha F30BEHTL 2011 - sputtered, wouldn't start, 4 stroke EFI - fuel problem

Thanks,

I have changed all external factors including fuel, tank, lines, bulb etc.

Could there be a crack in the diaphragm of the lift pump?