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Old 09-28-2009, 10:52 AM
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Gas in #7 and #8 Cylinders

I don't know if any of you have seen this before but after letting my 69 Camaro drag car sit a while, when I went to turn it over, the engine would not crank. Plugs were removed and when the engine was cranked, gas came out of the plug holes in #7 and #8 cylinder. I sure it was gas and not water because it was colored blue like the fuel (VP C12) and it evaporated right away. After rotating the engine and clearing the cylinders, the engine would crank ok with the plugs in. I have not fired it up yet. Often I would activate the fuel pump when it sits for a while to avoid having the gas evaporate out of the carb (Holley 4150). The car is usually kept in a hot garage (85 degrees). Could it be that when the engine was turned off last that the #7 and #8 intakes were in the open position? Maybe the gas did evaporate out of the carb and when I turned on the electric fuel pump initially the floats were stuck and a lot of gas could have poured into #7 and #8?

Any comments? Do you see any issues with firing up the engine? Should I throw some oil in the cylinders first in case the gas "washed" down the cylinders?

Any help would be welcome.

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Old 09-28-2009, 12:22 PM
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It could be the things you mentioned, or it also could be a vent problem.
If the vent doesn`t work the system will hold pressure after shut down building to the point it overcomes the needle and flooding results.
Most engines sit at a rear ward tilt so when the fuel came out of the carb it`s heading to the rear. Check the system, make sure it`s venting off after shut down as the fuel pressure should drop. Also check the fuel pressure while your at it. Keep in mind if the vent doesn`t function correctly it will effect the fuel pressure reading.
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Old 09-28-2009, 05:29 PM
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Yes, do put some oil in the cylinders.
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Old 09-29-2009, 08:03 AM
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Gas in #7 and #8 Cylinders

Thanks for your responses and suggestions.........I'll probably try firing it up on Friday.....hope it runs without issues.
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Old 09-29-2009, 12:17 PM
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Quote:
Originally Posted by Florida Camaro
I don't know if any of you have seen this before but after letting my 69 Camaro drag car sit a while, when I went to turn it over, the engine would not crank. Plugs were removed and when the engine was cranked, gas came out of the plug holes in #7 and #8 cylinder. I sure it was gas and not water because it was colored blue like the fuel (VP C12) and it evaporated right away. After rotating the engine and clearing the cylinders, the engine would crank ok with the plugs in. I have not fired it up yet. Often I would activate the fuel pump when it sits for a while to avoid having the gas evaporate out of the carb (Holley 4150). The car is usually kept in a hot garage (85 degrees). Could it be that when the engine was turned off last that the #7 and #8 intakes were in the open position? Maybe the gas did evaporate out of the carb and when I turned on the electric fuel pump initially the floats were stuck and a lot of gas could have poured into #7 and #8?

Any comments? Do you see any issues with firing up the engine? Should I throw some oil in the cylinders first in case the gas "washed" down the cylinders?

Any help would be welcome.
A competition engine should be treated like an aircraft engine and you have the tools to do this simply with an electric fuel pump, that is shut it off by killing the fuel first, let it run out the carb and quite, then shut off the ignition. Let it set with the carb more or less empty when not used this will insure that fuel doesn't vent into the engine when it isn't being operated. do not operate the pump unless the engine is to be started.

Yes, before you light it up next time a couple shots of light oil like Marvel Mystery Oil is a good idea.

Given that cars don't use wobble pumps to prime the engine but the carb has an accelerating pump which will provide the same service of priming the engine; the start up procedure would simply be to turn the fuel pump on to charge the float bowls, pump the accelerator pedal a couple times to prime the engine, start to crank it, then switch the ignition on. This is also a good procedure if you're running a lot of initial spark advance as the engine can gain some RPM on the starter before the ignition is switched on which helps prevent backfires while the starter is engaged.

Bogie
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Old 09-29-2009, 02:52 PM
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If you are starting off with dry bowls we do not recommend using the electric pump to refill the bowls as it can damage the floats and/or needle and seats. With an empty bowl same as a new carburetor install our recommendation is to prefill the bowls through the vent tubes.

In regards to the op issue with the fuel prior to restarting the engine is there still fuel in either bowl or does it empty one or both? Does the rear metering block have a power valve or plug in it?
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Old 09-29-2009, 03:10 PM
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Quote:
Originally Posted by Florida Camaro
Thanks for your responses and suggestions.........I'll probably try firing it up on Friday.....hope it runs without issues.
Check to be sure the oil hasn't been diluted w/gas during all this.

I do not see why it would be an issue to fill the bowls w/an electric pump- as long as the pressure is correct. If you had a mechanical pump, fill the carb through the vents to avoid unnecessary cranking.
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Old 09-29-2009, 07:51 PM
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Quote:
Originally Posted by cobalt327
Check to be sure the oil hasn't been diluted w/gas during all this.

I do not see why it would be an issue to fill the bowls w/an electric pump- as long as the pressure is correct. If you had a mechanical pump, fill the carb through the vents to avoid unnecessary cranking.
You seem to disagree with a lot of what we say and do but I guess we can continue to agree to disagree.

If you read our carburetor install manuals you will see we recommend filling the bowls through the vent on cars with electric pumps. Although it does not do it every time sometimes the fuel is pushed into the empty bowl faster then the air can escape and the result is that with a brass float it can collapse the float and on a nitrophyl float it can bend the float bracket. We have also seen stuck needle and seats from this as well.
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Old 09-30-2009, 04:40 AM
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Quote:
Originally Posted by Tech @ BG
You seem to disagree with a lot of what we say
You pregnant? lol

The only other thread I've responded to that you had also responded to was HERE.

You had said: "A 750 Demon will flow a little over 900 cfm."

I asked: So the obvious question is: "Why is it rated at 750?" A discussion regarding this ensued.

Hardly what I would call "disagree with a lot of what we say".

Back to the subject at hand- In my experience I have had no issues filling the float bowls w/an electric pump.

BUT- this is w/Holley (as well as Q-Jet, Carter and Carter-type) carbs- I have zero experience w/BG carbs- BG might have problems w/collapsed floats, bent brackets and stuck needle/seat assemblies that do not appear in Holley carbs or the other carbs I have filled using an electric pump. And the OP has a Holley- NOT a BG.

Holley doesn't recommend any particular procedure to fill the float bowls on a new carb installation, carb (4777) instructions HERE only say to start the engine. No warnings of impending failures due to the BG-related problems.

From a product liability standpoint, I can see a manufacturer giving the warnings that are mentioned.
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Old 09-30-2009, 05:25 AM
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What type of intake do you have, dual plane or open plenum? I would check the rear float level and the float. Might have collapsed or have a pin hole on the seam. I've found the latter before.

Last edited by sqzbox; 09-30-2009 at 05:26 AM. Reason: spelling again
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Old 09-30-2009, 06:02 AM
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Quote:
Originally Posted by cobalt327
You pregnant? lol

The only other thread I've responded to that you had also responded to was HERE.

You had said: "A 750 Demon will flow a little over 900 cfm."

I asked: So the obvious question is: "Why is it rated at 750?" A discussion regarding this ensued.

Hardly what I would call "disagree with a lot of what we say".

Back to the subject at hand- In my experience I have had no issues filling the float bowls w/an electric pump.

BUT- this is w/Holley (as well as Q-Jet, Carter and Carter-type) carbs- I have zero experience w/BG carbs- BG might have problems w/collapsed floats, bent brackets and stuck needle/seat assemblies that do not appear in Holley carbs or the other carbs I have filled using an electric pump. And the OP has a Holley- NOT a BG.

Holley doesn't recommend any particular procedure to fill the float bowls on a new carb installation, carb (4777) instructions HERE only say to start the engine. No warnings of impending failures due to the BG-related problems.

From a product liability standpoint, I can see a manufacturer giving the warnings that are mentioned.
No but I am beginning to think you are...... You also posted your disagreement with how we rate our carbs in another thread totally unsolicited but like you say back to the manner at hand.

Considering our carburetors use some of the same floats as the Holleys the chance is there for this to occur and it is not strictly a Demon problem as you would like to make it out to be. I AM fully aware that the op has a Holley and we were just trying to help and give CORRECT information even though he is not using our product.
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Old 09-30-2009, 06:28 AM
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Quote:
Originally Posted by cobalt327
Holley doesn't recommend any particular procedure to fill the float bowls on a new carb installation, carb (4777) instructions HERE only say to start the engine. No warnings of impending failures due to the BG-related problems.

From a product liability standpoint, I can see a manufacturer giving the warnings that are mentioned.
Actually if you look at their instructions for some of their race carburetors it has 2 different procedures listed for filling the float bowl. One for a mechanical pump and the other for an electric. In the one for the electric they ask that the pump be toggled on and off and not just left on so it does not damage the needle and seat.See page 3 on the link attached.

http://www.jegs.com/InstallationInst...10-O-80586.pdf
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Old 09-30-2009, 08:44 AM
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Gas in #7 and #8 Cylinders

Quote:
Originally Posted by sqzbox
What type of intake do you have, dual plane or open plenum? I would check the rear float level and the float. Might have collapsed or have a pin hole on the seam. I've found the latter before.

I have an open plenum intake. After the incident occurred (just once), I have not seen it happen again....both fuel bowls are holding good level and the vents seem to be working ok..this is of course just when the fuel pump is activated...I will know more when I fire it up and run for a while. Before that of course I will pull both bowls and check the condition of the floats etc. Just want to thank all of the responders for the advice and help.
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Old 09-30-2009, 01:10 PM
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As Cobalt327 recommended, pull your oil dipstick, if the oil has any smell of fuel change it.
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Old 09-30-2009, 03:14 PM
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Quote:
Originally Posted by Tech @ BG
Actually if you look at their instructions for some of their race carburetors
Interesting- IF the subject was Dominator carbs. Holley does not have such a recommendation for their universal double pumper series of race carbs, nor the 3310 or 1850 performance carbs but the intermittent powering of an electric pump at least allows the use of such a pump to fill empty bowls.
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