F15A - carburettor issue - won’t run for long (over-fuels) - any suggestions?

[Valhalla ll]

Hi,

I’ve got a low hours 2006 F15A which I’ve serviced after being stood/stored, however I’ve got issues with getting it to run properly again…

It was initially leaking and not running, so I’ve replaced (with genuine parts), the carb bowl gasket, float, diaphragm and O seals, and given it a good clean (I haven’t stripped it apart yet), as well as replaced the inlet manifold gaskets, fuel filter, and it’s running off a brand new battery and fresh fuel obviously, and I can get it to start from cold after priming, even without choke and it’ll run and pump fuel and water, but stalls after a minute and over-fuels.

Any ideas? The internals of the carb are clean visually and I replaced all the items above due to aging/hardening of said items. The engine was not stood/stored with fuel left in it, but obviously this doesn’t mean I could have a blockage somewhere…

I’m thinking a full strip down and getting an ultrasonic bath (?).

Any and all information would be appreciated.

Thanks,

Jim

[99yam40]

over fueling to me means the float is not shutting off the fuel going into the carb bowls.
the needle is not sealing off when the float rises when fuel gets high enough.
maybe trash in the seat, or float stuck, or not set properly.

or maybe the cold start enriching system is not turning off as the motor heats up, (if this motor has that and not a choke)

can you find your motor here ?
so a parts diagram can be looked at
Yamaha - Outboard - 15HP OEM Parts | Boats.net

[panasonic]

You might want to replace the float needle and check the needle seat for dirt or corrosion. You can clean the needle seat with a Q tip and some tooth paste...it has to be perfectly clean to seal.

[panasonic]

That float needle has a rubber tip, I believe ,and may be gone hard from age....

[ausnoelm]

I guess the really obvious thing…..how do you know it stalls because of “over fuel”? The very first thing to do is clean the carb properly, just looking at it isn’t cleaning it.