[English Impala]

Just fired up the Chevy after a two week hibernation & its running as rich as it ever has! Black smoke, stinking of petrol, sluggish, the car's just the same... .

Fuel pressure gauge shows 8 psi on tickover. Carb is an Edlebrock 600 4-barrel.

The carb is off Andy (58 Delray's) 58 which has a 350, so I guess it might want the mixture tweaking for my 305? Fuel pressure, is 8 too high? I asked a similar question a while ago on the NSRA but can't find the bloody thing!

Regarding setting the mixture, how? Many moons ago I had a special clear spark plug & you set the mixture until the right colour spark could be seen in the plug. I no longer have that & it wouldn't fit anyway! So, whats the best rule-of-thumb/basic set up for an Edlebrock as they are different to the Holley that I used to use?

 

[chevy2]

i'm guessing 8psi is too high,
try starting on 5-6psi,
to get the mixture right you'll need to get the motor up to operating temp,
only then can you set the mixtures correctly,
start off with the 2 mixture screws wound out about 2 turns each,
once the motors fully warm, gradually wind the screws in 1 at a time to lean it out,
once the idle drops off wind each screw out 1/4 of a turn,
you should be fairly close.

or use a vacuum guage using direct vacuum from the base of the carb,
adjust the 2 mixture screws trying to get the highest reading at idle.

 

[English Impala]

Thanks, just tried to adjust the pressure regulator & my metric allen keys don't fit! I'll buy an imperial set & try what you've said.

 

[kapri]

Yup, agreed. I wouldn't be looking at more than 5 -6 psi as well otherwise it can start pushing the floats up and dripping fuel in .

Don't forget to recheck your float levels and you have got a filter inline i take it ? Dry tank can soon loosen particles when fuels added and stick the floats up.

 

[Plumpcars]

Be wary of your pressure gauge when it's hot as well. On many of them the pressure on the gauge drops when the engine bay warms up. Checked mine the other day and it shows 1 !

 

[SG57]

Be wary of your pressure gauge when it's hot as well. On many of them the pressure on the gauge drops when the engine bay warms up. Checked mine the other day and it shows 1 !

I bet it ran OK Steve, a lot of old carbs used to run at 1lb. If you don't have new needles and seats 4lb would be a good start.

 

[Plumpcars]

Runs fine Roger but I know that some of these gauges are known to be inaccurate when warm. I do think that people overestimate how much fuel pressure they actually need to run fine on a street car though.

 

[Gary Mc]

Be wary of your pressure gauge when it's hot as well. On many of them the pressure on the gauge drops when the engine bay warms up. Checked mine the other day and it shows 1 !

OK I am guessing here as I don't know what type of gauge you have.

But IF

It is a liquid filled one, moon or similar and the reading goes wobbly on you, before you start swapping pumps etc there is a rubber plug on the side. It is a kind of blanking grommit. Pull it out and a bit of the magic juice that is in there will ooze out and all will be good.

If your gauge is not that type then ignore what i said.

G

 

[English Impala]

Pressure wound down to 4 psi, new filter fitted, sorted! Thankyou.

 

[bigyellataxi]

Cool, can I carry on washing up now??? :finger:

Do you want that blokes number re the bonnet???

Pressure wound down to 4 psi, new filter fitted, sorted! Thankyou.

 

[kapri]

Pressure wound down to 4 psi, new filter fitted, sorted! Thankyou.

Gary, nic eof you to come back and confirm that it works. Ther are often conversations in tech sections about the merits of different psi pumps, good to see real world results.

 

[English Impala]

About the only thing that my dad told me that I ever listened to was that manners & politeness costs nothing, but goes a long way!

The strange thing is that I am 99% sure that before we went away a couple of weeks ago (when the car was running fine) the fuel pressure was around 5 psi. On returning home it was just over 8psi & running as rich as they come??? Maybe those damned flesh-eating spiders have started adjusting my pressure regulator as well! Just wish I could train them to fit headlinings!

 

[58 delray]

glad you got it sorted gary, i was starting to worry there for a moment,

andy

 

[Plumpcars]

OK I am guessing here as I don't know what type of gauge you have.

But IF

It is a liquid filled one, moon or similar and the reading goes wobbly on you, before you start swapping pumps etc there is a rubber plug on the side. It is a kind of blanking grommit. Pull it out and a bit of the magic juice that is in there will ooze out and all will be good.

If your gauge is not that type then ignore what i said.

G

Interesting tip. Thanks Gary, must check mine now.:tup:

 

[mikeyboy]

Just install a stock mechanical fuel pump and forget about it.Large volume electric fuel pumps are a waste of time on a chevy unless you have a ton of horse power which your 305 wont have.

 

[English Impala]

Just install a stock mechanical fuel pump and forget about it.Large volume electric fuel pumps are a waste of time on a chevy unless you have a ton of horse power which your 305 wont have.

Problem is its a mid 90's Vortec engine & the cam doesn't have a lobe for a mechanical pump (I found out the hard way.....). The engine is an "M" series 305 which puts out 260bhp from the factory, so for a 305 its reasonably powerful.

 

[mikeyboy]

Problem is its a mid 90's Vortec engine & the cam doesn't have a lobe for a mechanical pump (I found out the hard way.....). The engine is an "M" series 305 which puts out 260bhp from the factory, so for a 305 its reasonably powerful.

Oh I see..

 

[langy]

To be honest Gary a Facet Red top would work with your engine and you wouldn't need the reg.

 

[Plumpcars]

OK I am guessing here as I don't know what type of gauge you have.

But IF

It is a liquid filled one, moon or similar and the reading goes wobbly on you, before you start swapping pumps etc there is a rubber plug on the side. It is a kind of blanking grommit. Pull it out and a bit of the magic juice that is in there will ooze out and all will be good.

If your gauge is not that type then ignore what i said.

G

Gary, just done that with my Moon gauge. How much juice to you let escape? Sure mine would empty itself if I let it!