carb flooding
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Joined: Dec 2009
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From: Macomb Michigan
carb flooding
so for the first time I took the carb out and rebuilt it. Even though I have only novice skills I think I did a relatively good job cleaning it up and putting everything back into place. After I started the engine fuel is squirting out of the pump hole on the carb. Quite a lot actually. Does that mean the float is stuck or could it be something else.
Thanks for any suggestions.
Thanks for any suggestions.
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Assuming that you installed all the parts and in their correct locations, it's most likely that you installed the needle valve retainer wire [hook] in one of the holes on the float arm. That is a 'no-no' as it can bind up the valve and keep that valve system from working properly. The hook should just be place over the center part of that arm...so that the valve will always work freely. Many rebuilder just throw the "hook wire" away.
(There are lots of other possibilities, but that one comes to mind.)
(There are lots of other possibilities, but that one comes to mind.)
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Joined: Dec 2009
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From: Macomb Michigan
Assuming that you installed all the parts and in their correct locations, it's most likely that you installed the needle valve retainer wire [hook] in one of the holes on the float arm. That is a 'no-no' as it can bind up the valve and keep that valve system from working properly. The hook should just be place over the center part of that arm...so that the valve will always work freely. Many rebuilder just throw the "hook wire" away.
(There are lots of other possibilities, but that one comes to mind.)
(There are lots of other possibilities, but that one comes to mind.)
will the wire stay on there that way?
Sorry forgot the details. It is a M4MC Rochester Quad in a 75'
Safety Car
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From: Southern Indiana
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Joined: Dec 2009
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From: Macomb Michigan
Also while we are at it; what is opening the secondary air flaps ? just air pressure/flow ? I know the primary choke closes it, but what opens it?
Thanks
Team Owner
Joined: Jan 2006
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From: Crossville TN
The hook will not slip off the float bar after assembly. The [upper] air valve is opened only by the incoming air flow. There are secondary "prevention" devices that keep the throttle plates and/or the air valve from opening, but once those details are satisfied, then airflow is the only force working to open them.
There is a spring which winds up as the air valve is opened; it determines the rate of opening. This upper air valve system is what sets the Q-jet apart from all the other carbs. It provides a "demand" type system which is self-regulating. Thus, a BIG cfm carb (750-800 cfm) can be placed on a hi-performance BB or on a 'base' engine SB by changing only the rods and jets.
Good luck on solving your flooding issue.
There is a spring which winds up as the air valve is opened; it determines the rate of opening. This upper air valve system is what sets the Q-jet apart from all the other carbs. It provides a "demand" type system which is self-regulating. Thus, a BIG cfm carb (750-800 cfm) can be placed on a hi-performance BB or on a 'base' engine SB by changing only the rods and jets.
Good luck on solving your flooding issue.
Melting Slicks
Joined: Mar 2008
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From: Austin Tx
As mentioned earlier, many people simply don't use the clip at all (Lars has even mentioned not using it if you have a problem with fuel bowl draining after shutdown). The fuel pump will provide enough pressure to push fuel past the needle when the float is lowered.
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Joined: Dec 2009
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From: Macomb Michigan
forgive my ignorance, but isn't the the purpose of the float to restrict the fuel flow? The float rises with the fuel level in the bowl which lowers the needle an restricts the amount of fuel that goes into the bowl.
It will stay on, that little bump where it's connected will keep it on.
As mentioned earlier, many people simply don't use the clip at all (Lars has even mentioned not using it if you have a problem with fuel bowl draining after shutdown). The fuel pump will provide enough pressure to push fuel past the needle when the float is lowered.
As mentioned earlier, many people simply don't use the clip at all (Lars has even mentioned not using it if you have a problem with fuel bowl draining after shutdown). The fuel pump will provide enough pressure to push fuel past the needle when the float is lowered.
Le Mans Master
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From: Oxford MA-----You just lost the game!!!!
Scott
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From: Macomb Michigan
got it all back together and there is still fuel coming out the opening of the pump shaft. It seems to be not as much as the first time but still it's coming. I am very sure that the new float and needle are working fine. Is there anything I am missing here?
thanks
Norman
thanks
Norman
Melting Slicks
Joined: Mar 2008
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From: Austin Tx
There are only a couple of things I can think of.
A problem with the float, it's set to high, or it's binding, or sinking. Did you replace the float when you rebuilt it? If you didn't before, you want to make sure to replace the float with a brass float.
Are you using a mechanical fuel pump, or an electric one? If electric, was there a regulator somewhere that maybe didn't get put back on. An electric fuel pump will provide to much pressure, and will push fuel past the needle, that's why a regulator is needed to use one with a carb.
A problem with the float, it's set to high, or it's binding, or sinking. Did you replace the float when you rebuilt it? If you didn't before, you want to make sure to replace the float with a brass float.
Are you using a mechanical fuel pump, or an electric one? If electric, was there a regulator somewhere that maybe didn't get put back on. An electric fuel pump will provide to much pressure, and will push fuel past the needle, that's why a regulator is needed to use one with a carb.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
got it all back together and there is still fuel coming out the opening of the pump shaft. It seems to be not as much as the first time but still it's coming. I am very sure that the new float and needle are working fine. Is there anything I am missing here?
thanks
Norman
thanks
Norman
Scott