Leaking carb
July 13th, 2016, 07:22 PM
#1
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Leaking carb
I have a 65, 330 4bll in a 65 Cutlass. It has a Rochester 4 jet carb and it's leaking gas onto the exterior of the intake manifold. It starts to leak as soon as the engine is started and continues after the engine is shut off until (I presume) the bowl is empty. It idles fine and runs smooth on the road so it must be an external only leak. It does not appear to be leaking around the fuel inlet or filter housing. I snugged up the top hold down carb bolts but that didn't help. Any ideas as where to look for the cause of the leak. It leaks bad enough that I don't feel it is safe to drive.
July 14th, 2016, 05:28 AM
#2
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An older Rochester carburetor may weep fuel between the fuel bowl and air horn but it shouldn't be fast enough to puddle on the intake manifold. I know the Quadrajets were notorious for bad threads at the fuel inlet, I'm not sure if the early 4 jets had the same problem. How long has it been since the carburetor was rebuilt?
July 14th, 2016, 06:59 AM
#3
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I just got the car so I don't know when it was last rebuilt. The documentation I got with the car indicates the carb was cleaned and ajusted about 5000 mi.ago, but that was 10 yrs. ago. I hope to pull and inspect today.
July 14th, 2016, 07:29 AM
#4
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Todays fuel raises issues with older rubber parts and tends to leave powdery residue when the car sits and the fuel evaporates in the carb. It tends to clog things when fuel is returned. It could be a few things causing your issue. I would take the carb off and rebuild if its been that long ago.
July 14th, 2016, 09:52 AM
#5
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the gasket should be above the fuel level.
probably dirt holding the needle open. Try blocking fuel inlet- pinch the FP inlet off- run the carb out of gas, then restart, the inrush of fuel over a now wide open needle may flush it out ok
probably dirt holding the needle open. Try blocking fuel inlet- pinch the FP inlet off- run the carb out of gas, then restart, the inrush of fuel over a now wide open needle may flush it out ok
July 14th, 2016, 11:36 AM
#6
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Also likely causes are a mis-adjusted float or a leaking/saturated float.
July 14th, 2016, 07:40 PM
#7
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Thx for the responses. I pulled the carb and took of the top. I couldn't see anything wrong, the carb was very clean inside. I put a very thin coating of atv on the top gasket as well as the filter gasket. I checked the float levels and they were OK. Put it back together, installed it and everything seens fine, no more leaks!
July 15th, 2016, 05:44 AM
#8
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If you mean RTV I would go ahead and rebuild the carburetor now. You shouldn't use gasket sealant of any kind on a carburetor. It may eventually break free and clog some of the passages in the carburetor.
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