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Old 07-13-2012, 07:27 PM
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Default 305 carburetor

Looking for a rochester carb 4 bbl merc.# 1347-9661a3
I have put in a new fuel pump and 2 people have rebuilt it and gas still comes over the top and runs down the intake. Fuel pressure is 6psi.The one guy told the float is set very low he has tryed it at different heights. what do you guys think?
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Old 07-13-2012, 08:17 PM
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Sounds like the gasket under the needle seat is leaking . Can also be a bad float or needle . These are the three things that control fuel flow and fuel level , if any one of these are bad the carb will flood .
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Old 07-13-2012, 08:48 PM
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Try the Carburetor Shop in Ontario, CA. Google them. They have done an awesome job for me in the past.
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Old 07-13-2012, 09:18 PM
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put a new float in it and a new needle and seat also with a new gasket
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Old 07-13-2012, 09:36 PM
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Originally Posted by dennis r
put a new float in it and a new needle and seat also with a new gasket
Was it flooding before it was rebuilt ? Is the needle hanging towards the float or away from it , talking about the little needle hanger . It should be toward the float . Seat snugged down good ? These carbs don't just flood for no reason , something is being overlooked .
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Old 07-13-2012, 09:41 PM
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I will look at it in the morning
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Old 07-14-2012, 05:35 PM
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Well that was not it I put on a fuel pressure regulator and it maxs out at 6 psi . th e carb runs over at that but if I turn it down to 4/5psi it will run just fine why is the new fuel pump to much psi for the carb.
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Old 07-16-2012, 04:31 PM
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A properly sealing float/needle combo will seal at up to 9 psi.
6 psi is perfectly fine.

You need to check your float for a leak (if it's brass) or see if it may be hitting something that keeps it from closing all the way, or simply replace the needle and seat.

MC
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Old 07-16-2012, 06:52 PM
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I did all that new float new needle and seat
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Old 07-16-2012, 08:08 PM
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This might sound crazy but you might have a "bad" new needle valve and seat...it should hold 8~9 psi if it's correct.
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