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Posted on Mar 14, 2009
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Float hieght for 1984 IT 490

Leaking fuel from over flow tube. Needle and seat do not leak, pet **** valve does not leak. Float level is wrong?? What is the height and how to check. Thanks Bill

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  • Expert 126 Answers
  • Posted on Mar 16, 2009
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Joined: Oct 16, 2008
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Not sure of the exact height, but if you hold the carb level with fuel hose attached and pushing float up with finger, turn on petcok and slowly lower the float until it is just above horizontal. at this point, gas should start to flow out of the needle & seat.

if float turns off gas too soon, then engine will starve.

if float doesn't turn off gas, then it will flow out of the carb overflow tube.

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0helpful
1answer

Why is my carburetor leaking fuel after I turn off my motor

It is most likely that your shut off valve is leaking (as fuel flow should be shut off with no vacuum applied to it). If the float level is okay, and it must be set very precisely at 0.413 - 0.453 inches with the carb tilted no more than 20 degrees and no less than 15 degrees, (if the float level is the problem such that the fuel supply would be too high in the float bowl and depending on how far out it is set ie how high the fuel is allowed to rise in the float bowl it would likely be leaking out the overflow and not the carburetor itself). As unlikely as it would be to have fuel flowing out the accelerator pump circuit and discharge port you would easily be able to identify such a leak by seeing it flow out of the accelerator pump discharge port in the front part of the carb throat. If the needle and seat are not sealing and fuel flow was available from the shut off valve as it should not be with no vacuum applied to it then it would not matter that the float level was set correctly because it would continue to flow past the needle ans seat when the float had risen to the proper shut off point. In this case it might leak out of the main discharge port before the level became high enough for it to leak out of the overflow or it might leak out both. It is doubtful that a defective enrichener would cause a leak because the fuel would have to rise to high to emerge from the enrichener discharge ports. It might leak out the off idle discharge ports but these are behind the venturi piston and the butterfly valve so you would have to raise the former and open the latter to see if fuel was emerging from these ports. I have not dealt much with H-D CV carbs but my understanding of them leads me to suggest the above. SO, a leaking carb with the engine shut off is most likely to be a result of a defective fuel tank valve so first remove the fuel hose from the shut off valve and see if there is fuel draining from the nipple at the valve or if you take it off at the carb if there is any fuel leaking out of the fuel line you removed from the carb.....There should be no fuel flow with the engine off and no vacuum. If there is no fuel flow here there should be no fuel flow from the carb unless the float level is out and the fuel level in the float bowl has risen too high before the fuel valve shut of fuel flow. Even so the fuel leak should not be continuous but only as much as there was fuel in the fuel line and carb downstream of the shut off valve. If the leak is continuous you know the valve is the first problem and then you also have a float level setting that is out allowing too much fuel into the float bowl and/or the needle and seat are not sealing and shutting off the flow when the float rises to the proper shut off height. Or, you could have a gasket leak at the float bowl. If there is no fuel flow from the fuel shut off valve and the float level is correct there likewise should be no flow from the accelerator pump (or any other circuit) because the fuel level would never be high enough to flow out the discharge the accelerator discharge or other ports. Remember that the accelerator pump check valve only operates when the fuel is being forced out of the accelerator pump circuit ie the valve does not stop or control fuel flow into the accelerator pump diaphragm area, it only stops flow back to the float bowl area when fuel is being pressurized to force fuel up and out the discharge port. I hope this helps somewhat in diagnosing your leak.
0helpful
1answer

Overflowing Carbs again!!!

recheck and clean /adjust floats pet **** doesnt stop fuel in bowl if floats out of adjustment or valve sticking/debris will allow fuel to constant flow
0helpful
1answer

Yamaha v-star float bowl adjustment

No. Wrongly adjusted float height makes the engine fail to run.
If you get over flow leak (from the overflow hose) your fuel needle inside the carburetor simply does not close the gas supply hole firmly even if the floaters still pressing it against that hole.
That is because the over flow holes on a carburetor are so far above the floaters that even with the float height wrongly adjusted, the fuel needle should stop the gas from overflowing and simply made your fuel mixture too rich.
0helpful
1answer

Gas leak out or the carburetor

Thiis usually caused by a failure of either the float valve or the float itself.

Bad float needle valve: If some dirt or other particle gets stuck on the needle valve or seat, the valve will not be able to completely close and fuel will continue to flow into the bowl and eventually overflow. A new needle valve and seat are < $5.00 on-line.

Bad float: If the circular float gets a hole in it, fuel will get inside and the "float" will get heavy and no longer float on top of the fuel in the bowl. Because it doesn't float it will not rise high enough to push the needle up into the seat and keep extra fuel from entering the bowl. A new circular float is < $10 on-line.
0helpful
1answer

2003 Honda CRF 150 F gas leaking out the carburetor vent tube

needle not attached to float properly or a hair or the like not allowing the needle to close off properly
1helpful
1answer

Honda motor only runs with choke fully on.

Lets back up and regroup on the carb cleaning.

Before you start.... if you have a digital camera take "close up" PICTURES of the linkages and springs attaching to the carb. If this is your first time you will be so glad you did. You can always delete them later if you don't need them. :)

Here is what you need to do:

1. Fuel selector off
2. Remove float bowl mounting screws and nut
3. Remove the BRASS Jet / Orifice in the very bottom of the venturi tube inside the pickup tube. (Flat blade screwdriver) Hold the Orifice up to the light. You should see a pinhole. If it is not clear clean the orifice but do not force anything through the hole.
4. Underneath the Orifice there is yet another BRASS tube that you need to remove. (Flat blade screwdriver) Make sure all of the holes in the tube are clear. The tube will be over 2 inches long. Clean it and reinstall it.
5. Reinstall the Orifice.
6. Using a catch fuel container turn on the fuel selector. Fuel should flow at a good rate. GENTLY lift the float assy level and make sure fuel flow shuts off. When you drop the float again fuel should flow.
If you do not have fuel flow at this point the needle and seat will need to be inspected. Fuel selector OFF.
(The following procedure is to be done only if there is no fuel flow with fuel selector on.)
a. Remove the silver float pivot pin retaining screw
b. Drop the Float down (The needle will come off with the float. NOTE the position)
c. Inspect the tapered rubber of the needle If should be pointed. If it is not pointed then the rubber tip is stuck inside the seat.
d. Clean the seat hole ONLY if obstructed. (Easily damaged)
e. FUEL Selector on then off fuel should rapidly flow through the needle seat.
f. Renistall Float and needle making sure to get the pivot / hinge pin installed correctly and reinstall the silver retaining screw.
g. Fuel selector ON. Raise and lower float checking for free movement with fuel flow when lowered and stopped when the float is raised level.

NOTE if fuel does NOT stop when float is level you will need to bend the float tab (tab up if level is too high or tab down if level is too low) where the needle attaches to the float assy until it does.

7. If there still is no fuel flow at this point remove the fuel hose from the carb and check fuel flow. If no flow check that gas tank exit hole, fuel filter (if installed) and the selector valve assy for obstructions.

Reassemble connections.

FUEL FLOW IS GOOD

Step 8 is VERY important"

8. BEFORE you install the float bowl inspect the bowl nut. There are 2 holes in the side of the nut where it screws in to the bottom of the carb that must be clear.

9. Install Float bowl mounting screws and nut. Check for leaks.

10. Test engine.

That should do it.

Thanks for using FixYa.

Kelly

Final note... if it does NOT start after this there are other problems we can discuss. i.e compression and spark "how to."
1helpful
1answer

My Toro Mower is running real rough, and doesn't have the power it did. I already cleaned the auto choke and put in new gas, as well as changning the spark plug, and air filter, and changing the oil. Any...

Hi and welcome to FixYa. I am Kelly.

Does it sound like it is running rich (Black smoke) or lean can not reach normal speed)?


In either case. Here is how to clen the carb properly:

Before you start.... if you have a digital camera take "close up" PICTURES of the linkages and springs attaching to the carb. If this is your first time you will be so glad you did. You can always delete them later if you don't need them. :)

Here is what you need to do:

1. Fuel selector off
2. Remove float bowl mounting screws and nut
3. Remove the BRASS Jet / Orifice in the very bottom of the venturi tube inside the pickup tube. (Flat blade screwdriver) Hold the Orifice up to the light. You should see a pinhole. If it is not clear clean the orifice but do not force anything through the hole.
4. Underneath the Orifice there is yet another BRASS tube that you need to remove. (Flat blade screwdriver) Make sure all of the holes in the tube are clear. The tube will be over 2 inches long. Clean it and reinstall it.
5. Reinstall the Orifice.
6. Using a catch fuel container turn on the fuel selector. Fuel should flow at a good rate. GENTLY lift the float assy level and make sure fuel flow shuts off. When you drop the float again fuel should flow.
If you do not have fuel flow at this point the needle and seat will need to be inspected. Fuel selector OFF.
(The following procedure is to be done only if there is no fuel flow with fuel selector on.)
a. Remove the silver float pivot pin retaining screw
b. Drop the Float down (The needle will come off with the float. NOTE the position)
c. Inspect the tapered rubber of the needle If should be pointed. If it is not pointed then the rubber tip is stuck inside the seat.
d. Clean the seat hole ONLY if obstructed. (Easily damaged)
e. FUEL Selector on then off fuel should rapidly flow through the needle seat.
f. Renistall Float and needle making sure to get the pivot / hinge pin installed correctly and reinstall the silver retaining screw.
g. Fuel selector ON. Raise and lower float checking for free movement with fuel flow when lowered and stopped when the float is raised level.

NOTE if fuel does NOT stop when float is level you will need to bend the float tab (tab up if level is too high or tab down if level is too low) where the needle attaches to the float assy until it does.

7. If there still is no fuel flow at this point remove the fuel hose from the carb and check fuel flow. If no flow check that gas tank exit hole, fuel filter (if installed) and the selector valve assy for obstructions.

Reassemble connections.

FUEL FLOW IS GOOD

Step 8 is VERY important"

8. BEFORE you install the float bowl inspect the bowl nut. There are 2 holes in the side of the nut where it screws in to the bottom of the carb that must be clear.

9. Install Float bowl mounting screws and nut. Check for leaks.

10. Test engine.

That should do it.

Thanks for using FixYa.

Kelly
2helpful
2answers

Engine stalling due to too much fuel. Fuel in crankcase.

sounds like your float in the carb is stuck or the needle valve is bad. remove the bowl and push the float up to level. this should stop the fuel flow. be aware that only slight pressure should be needed.if it does not ck the needle valve. also mak sure you float is not damaged.
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