Carburetor Question

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Oct 10, 2011 | 05:40 AM

briaineo

Thread Starter

Racer

Joined: Nov 2005

Posts: 340

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From: Dublin

Carburetor Question

Bought a new summit racing carb had a back fire in the carb and the fuel that was in the bowls has drained into the oil. Here's the carb I think its holly based

I've never opened up a carburetor before.

I'm guessing I blew the seats ( actually not too sure what that means )

Any idea what happened? Or how to fix?

thanks

Oct 10, 2011 | 07:08 AM

joewill

Safety Car

Joined: Sep 2007

Posts: 4,458

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From: Indy Indiana

how do you know the fuel drained into the oil? if it did that, then you have a much bigger problem than the carb.

Oct 10, 2011 | 07:11 AM

Roco71

Melting Slicks

Joined: Jul 2009

Posts: 3,264

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From: Vero Beach FL

I bought one of these last week The floats where both set to high I had to adjust them both. Are you sure that there is no fuel in the bowls and they aren't full . Its hard to tell if they are completely full or empty by looking through the windows. You can see the level when its somewhere in between.

Oct 10, 2011 | 07:49 AM

stingr4y

Racer

Joined: Mar 2005

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Also, be aware that oil can smell like fuel when gas drains past the rings when too rich, or flooded.

Was it running fine before the carb change out?

Fresh rebuild?

Oct 10, 2011 | 08:10 AM

Ganey

Race Director

Joined: Apr 1999

Posts: 11,520

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From: CORVETTE 77 385 C.I. TEXAS

Quote:

Originally Posted by briaineo

Bought a new summit racing carb had a back fire in the carb and the fuel that was in the bowls has drained into the oil. Here's the carb I think its holly based ...

Any idea what happened? Or how to fix?

thanks

A back fire can blow the power valve. The 'Summit' carbs are said to not have backfire protection.

Holleys built since '92 have backfire protection.

Oct 10, 2011 | 10:47 AM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

Your timing is likely way off the mark. You need to set the timing properly first....then try out the carb. Fuel in the oil is NOT a good thing. Be careful and have a fire extinguisher readily available.

Oct 10, 2011 | 12:24 PM

Easy Mike

Team Owner

Joined: Jun 2000

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From: Southbound

Cruise-In II Veteran

Quote:

Originally Posted by briaineo

...Or how to fix?...

Put the Q-Jet back on. A back fire through the carburetor is a timing issue provided you do not have anything physically keeping an intake valve open.

Oct 11, 2011 | 09:16 AM

briaineo

Thread Starter

Racer

Joined: Nov 2005

Posts: 340

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From: Dublin

Thanks for all the advise

the bowls are defo empty.

They used to hold the fuel until the backfire.

I'll get new plug wires and a timing light and have a go at setting the timing.

The carb I originally took off wasnt a Q-Jet it was a Holley 1850-4 (4160 series) i'm gonna get a rebuild kit for it. And put it back on.

The problem with the Holley 1850 was that was on the car when I bought it was: After I would turn the engine off the carb would still allow fuel to visibly leak constantly into the engine. ( This a float level problem? )