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Is my emulsion tube bad?

1

1999john25hp

Member
I’m getting a film of oil on and around my carburetor. I replaced the needle valve and seat and float. I adjusted the float so that it is basically parallel to the carburetor housing when held upside down. The needle seems to seat well, because if I hold the carburetor upside down and blow air into the gas line port, the needle blocks the air and it pressurizes (at least to some degree—I don’t have a pressure tester).

But when I reinstall the carburetor and squeeze the primer bulb on the gas line, it never gets and stays firm. I still hear gas flowing. Is there something else in the carburetor that could be leaking besides the needle valve? I replaced all the gaskets that came in the rebuild kit and tightened the screws to the float and the bolts to the engine pretty firmly.

I suspect the emulsion tube. The main tube comes out straight, but there is a little tube in tbr middle of the main tube that comes out an an angle and contacts the inner diameter of the main tube. Is that right?

Is there something else I should check? Maybe the needle valve is still the problem?

2000 Johnson 25hp J25RSSE
 
It left the factory with the little tube at an angle !----Do not touch it.-----Take fuel pump apart and inspect diaphragm.----Replace if ruptured.
 
Reed valves would have nothing to do with bulb not going hard.----You have a leak somewhere in the carburetor or fuel pump.-----Or the manual pump ( bulb ) is defective.
 
As you squeeze the bulb pumping fuel into the carb normally the float goes up & eventually shuts the inlet needle. This happens before the fuel reaches a level where it "overflows" into the venturi .

If the bowl vent is plugged, instead you begin to pressurize the fuel bowl as it fills and fuel will flow up the emulsion tube & idle circuit thus essentially flooding the carb into the manifold or out the front depending on tilt angle simpliy because you have applied pressure to the fuel bowl that should be vented to atmosphere. This will happen before the float rises enough to shut the needle.valve. You can squeeze the bulb forever.

I believe the bowl chamber is vented thru a small hole in the carb body (with carb inverted look for a small hole somewhere in the surface surrounding the stem/orifice tube assembly). I think the other end opens below the welch plug. It's been a long time & I'm reaching into the dark brain matter here.
 
Droid said:
As you squeeze the bulb pumping fuel into the carb normally the float goes up & eventually shuts the inlet needle. This happens before the fuel reaches a level where it "overflows" into the venturi .

If the bowl vent is plugged, instead you begin to pressurize the fuel bowl as it fills and fuel will flow up the emulsion tube & idle circuit thus essentially flooding the carb into the manifold or out the front depending on tilt angle simpliy because you have applied pressure to the fuel bowl that should be vented to atmosphere. This will happen before the float rises enough to shut the needle.valve. You can squeeze the bulb forever.

I believe the bowl chamber is vented thru a small hole in the carb body (with carb inverted look for a small hole somewhere in the surface surrounding the stem/orifice tube assembly). I think the other end opens below the welch plug. It's been a long time & I'm reaching into the dark brain matter here.
Click to expand...
Thank you. I just checked that and maybe that was part of the problem!
 
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