MARVEL SCHEBLER FLOODING

Have a mf to 35, ran w/ engine noise. replaced 1 sleeve and cylinder, 2 valves, head gasket, lapped valves. Have a gas tank off a lawnmower sitting on top of engine now providing fuel until i verify it runs , flooding, rebuilt carb, still flooding, replaced needle and seat w/oem- still flooding- pressure fed- no pump- any ideas?Thanks.

It could be one side of the float is filled with fuel.

Open it back up and give the float the shake test, listen for fuel inside.

Take the seat and inlet fitting out back out, clean the casting thoroughly. Some have a screen in the fitting, be sure it is clean.

If the float is good, put it back on, look to see if it is straight, not hitting the bowl, and both pontoons are the same height. With the carb upside down, there should be about 1/8" between the top of the float and the bowl gasket, or the float parallel with the gasket. If not, bend the tab over the needle to adjust the float level. Do not put pressure on the needle, do not bend the frame of the float, only the tab.

Before putting the bowl back on, hold the base upside down, float resting on the needle, suck on the inlet fitting, put your tongue over the hole. It should hold vacuum. If not, there is still a problem with the needle/seat. (I know, sounds gross, but not fatal, remember to spit!)

The incoming fuel and the fuel line must be clean! It only takes a tiny speck of trash to hold the needle valve open. I like to get the fuel flowing out the line before connecting it to the carb fitting to flush out anything that may have been missed.

Also be sure the carb is actually flooding. A true flooding carb will sit and drip with the fuel valve on and not running. It is normal for an updraft to loose a few drops of fuel following a failed choke assist start.

There is a lot of info online for that carb. Do some searching, should find complete rebuild and setting specs.

Easy test of the float is to throw it in a bowl of water.

(quoted from post at 17:39:50 09/12/18) Easy test of the float is to throw it in a bowl of water.

Click to expand...

A more useful test that's not much tougher to do is to hold the float underwater in a container of warm water.

Any leak/pinhole will bubble profusely.

The problem is you have a Marvel Schebler carburetor. Every one I have
seen does that. Can you replace it with another carb that was used on
that modle?

If it's still leaking you might try a little metal polish and a Q-tip on the float valve seat.

Remove bottom bolt.
Install brass fitting with 18" clear hose on it.
Hold open end of hose above carb.
Turn on gas flow.
Gas will rise in hose showing you fuel level inside carb.
adjust float accordingly.

Sometimes the float will drag against the sides of the bowl.

Have seen wear at the point the needle contacts the float cause flooding. A dimple forms on the float tab over time that the needle hangs up on. If that is the case, take the float and set the tab on a hard surface and using a rounded punch or whatever lightly tap the dimple out flush from the side opposite the dimple. then turn the tab back over and finish with a fine stone.

Had this happen on two Cub Cadet lawnmowers and my old Ford 2N which is MS equiped.

t is probably not flooding. Are the plugs dripping wet with gas? If not it is just the gas running back down out of the manifold because you were cranking it with it choked and it didn't start.