Merc 50 hp Bottom Carb Leaks

[Philn]

I have a 1994 Merc 50 hp 3 cyl two stroke.

A couple hours after being run gasoline starts leaking slowly out of the bottom carb throat.
Looks like gas is coming out of the small pipe in the throat and also may be coming out of the back of the throat.

Motor runs ok and no leak apparent when running at idle for 10 minutes.
Maybe needle/seat has essentially a slow leak???

Any suggestions would be appreciated.

Thanks

 

[Barnacle_Bill]

Time to rebuild the carbs.

 

[Philn]

No Title

I pulled the carb, cleaned it and blasted with air.
Put in a carb kit consisting of new gaskets, idle mix screw, needle. No seat with this kit. Looks like it is a press fit.
Float was ok, no gas in it.
Put it back together, ran ok, no leaks.
Stopped engine, trimmed up.
Carb still leaks, coming out of the small orifice tube (see attached picture) and also looks like gas coming out from further back in the carb also.
What would cause this? Is it a needle/seat thing or could it be something else?

 

[Texasmark]

Your float may not be adjusted properly. The needle valve is letting more fuel into the bowl when you tilt up due to the fact that either it's defective or there isn't enough pressure from the float arm to overcome the incoming fuel pressure......which isn't much, but apparently enough.

If you have the rubber tip on your needle that's probably all there is to it. The needle needs to be a perfectly symmetrical cone, no marks on it of any kind. Setting of the float is usually such that the float is parallel with the carb to bowl mounting flange when carb is inverted and bowl is on top, carb flange horizontal.

Quick check is to drop the bowl on that carb and with your finger holding the bowl up parallel, as described above, squeeze the bulb. If you don't get any fuel coming out of the carb then your needle is sealing properly and the problem lies with the bowl pressure. 3 things there: Adjustment as described or measured with the proper dimension, float water logged and not floating adequately under pressure.....pressure required to seal off the needle valve, or binding float arm linkage which will not allow the float to raise to the required level to shut off the fuel.

 

[Faztbullet]

Also could be a saturated float.....

 

[quicktach]

Rebuild in order - all carbs. At the very least, disassembly and cleaning and checking to spec.