Boat smoking brown and fuel smell when in idle sta

What could be the cause of big brown smoke when boat is in idle state ?

what do you suggest ? at which level should I check ?
Too much fuel, mix screw not properly set ?

regards
serge

You're grasping straws and not understanding proper carberatur tuning

Hollywoodien,

Sorry i do not understand what you try tout explain to me.
Il do not understand carb yes, but I manage tout change parts with repaire kits with good help on this

So I think my question are clear for carb expert in this forum.
For fuel in water I have ben told to adjust float which in my case is black without extern screw. So how tout ajustable it properly ?

Thé second thing I was simply asking was what coule beaucoup réas on of big brown smoke in idle state?

THanks for your help
Regards

From a quote on your other thread:

It sounds like your carburetor needs adjusting. I would start with the float bowl chamber. If the float is not adjusted properly, then 2 things are likely to happen:

1 - Float is adjusted too high: Too much fuel will enter the float bowl and the excess fuel will dump directly into the carburetor causing a rich condition. I had a float stuck open and the engine ran very rough in the low RPM range. Black smoke poured out the exhaust.

2 - Float is adjusted too low: Not enough fuel in the float bowl. The engine starves for fuel at higher RPMs. The engine may appear to run OK at low RPMs, but sustained higher RPMs will often cause the engine to stumble and run very poorly until RPMs are lowered and fuel re-fills the float bowl chambers.

Link below to the Holley Carburetor site for float adjustment:

LINK to video

One challenge with the Holley 4160 Marine carburetor, is that there is no "sight glass" window for easy fuel level viewing. This makes for some trial-and-error adjustments. One typical starting point is to remove the fuel bowl and hold the assembly upside down. The top of the float should be parallel with the top of the float chamber.

(The QuickFuel M-600 marine carburetor is based on the Holley 4160, but the QF unit has several upgrades. One major upgrade is the site glass window and float adjustment hardware on the top of the fuel bowl.)

JQ