351W running rough

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Jul 23, 2014 | 04:20 PM

Ab73ford

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351W running rough

Hey Guys
I'v got a 351 with a 302 cam in it Edelbrock performer manifold 600CFM carb.
For some reasion i can't get this thing to idle right. i have messed with the timeing, with the carb. The motor seam like it has good power

Problems

I'v got fuel in the oil
will not idle at normal rpm's
spark plugs are black
going though alot of gas
gas and air mix screws don't do anything

Things I have check

i'v check timeing
opened carb and check floats and seats
replaced manifold gaskets
changed carbs (neibor had an 700cfm carb)
fuel pressure is about 4lbs i think if the gauge is working right

anybody have any good ideas

Jul 23, 2014 | 04:34 PM

gatorfor88

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From: Panama City

Sounds like the fuel pump is leaking into the block. That is about the only way to get fuel in oil, and will cause just about everything you describe.

Jul 23, 2014 | 04:39 PM

Ab73ford

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ya i was thinking about that. its a new pump i guess it could be defect.

Jul 23, 2014 | 05:45 PM

Canus

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From: Spencer Mountain, NC

Indeed it sounds like a fuel pump problem. Also, ensure you are using the correct firing order. The early 302 used a different firing order than the newer 302 which is the same as the 351.

Jul 23, 2014 | 07:57 PM

Ab73ford

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well I replaced fuel pump and oil. still runs like crap. when it idles it reves up (1200 RPM )and down like its going to die. I cant get it to leave out.

Jul 23, 2014 | 08:42 PM

0ldman

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What carb? Sounds exactly like my Holley 600 vacuum secondary did the first time I built it, even the gas in the oil.

The secondaries were leaking constantly. I had power but it would flood out, foul plugs, etc. It flooded so bad the oil smelled of gasoline.

If it is a Holley I'd turn the rear float in until it cuts fuel to the secondaries all together, see if that corrects it. If so you need a new gasket.

Jul 23, 2014 | 09:25 PM

OldMetal

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From: US/Baja border

Your either getting too much fuel or too little air, what is your vacum reading?

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Jul 24, 2014 | 07:52 AM

Jklnhyd

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From: Pasadena, Ca

If your mixture screws do nothing, your power valve is blown.

Jul 25, 2014 | 04:41 PM

#10

Ab73ford

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I didnt think Edelbrock had power valvees? I thought that was a Holly thing. I think the air mix screws aren't working is because I can't get the idle down low enough.

Anther thing when i close the choke flap for a second the motor idels up???? I am guessing that means i am lean??? and the carb make a funny vacuuum noise that's not consistant almost like a gergal maybe i am crazy

Jul 25, 2014 | 05:00 PM

#11

0ldman

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Sounds like the carb is dumping fuel, but closing the choke should make it stall out and flood. Even the gurgling sounds like flooding.

You are correct, Edelbrock doesn't use power valves.

Jul 25, 2014 | 05:22 PM

#12

Ab73ford

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if it was flooding would that mean my float out of ajustment and or the seats not seating.?

Jul 25, 2014 | 06:55 PM

#13

0ldman

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I'm not completely up to speed on the internals of the Edelbrock carbs but there are usually lot of different things that can cause flooding. If the rods aren't in the jets it would be flooding and running extremely rich. I think that may have been my problem after I cleaned my Edelbrock.