Gasoline smell in cabin

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Billbo

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Hi all. Just wondering if anyone can help. I have installed an Edlebrock performer 1405 600cfm carb. All works quite well although when I give it wot for 5 seconds of more I will get a gasoline smell in the cabin after I back off and then it goes away. Only at wot. There are no leaks what so ever. All other throttle positions is o.k. Before I had a Holley 650cfm vac secondary carb installed and that did not have that problem no gas smell. Does anyonw know why the Edelbrock does it?
Regards
Billy D...
 
Billbo said:
Hi all. Just wondering if anyone can help. I have installed an Edlebrock performer 1405 600cfm carb. All works quite well although when I give it wot for 5 seconds of more I will get a gasoline smell in the cabin after I back off and then it goes away. Only at wot. There are no leaks what so ever. All other throttle positions is o.k. Before I had a Holley 650cfm vac secondary carb installed and that did not have that problem no gas smell. Does anyonw know why the Edelbrock does it?
Regards
Billy D...
Click to expand...
Billy,
Edelbrock carbs are a very simple carb to work on. Pretty much a set and go affair.

Do you have a pressure regulator installed between the pump and carb? These carbs like 4-5# of pressure. Anymore than that and it will hold that fuel bowl up, over filling and eventually leak around the top gasket.

You can check this by pulling the airhorn. There are two cavities behind the secondaries, if they have fuel in them then the fuel is bypassing the gasket. While you have the airhorn off, check the float level as too much fuel pressure will bend the little tang that contacts the float needle which in turn affects the float level. I hope this helps you.

Good luck,
 
Tinmannz said:
Billy,
Edelbrock carbs are a very simple carb to work on. Pretty much a set and go affair.

Do you have a pressure regulator installed between the pump and carb? These carbs like 4-5# of pressure. Anymore than that and it will hold that fuel bowl up, over filling and eventually leak around the top gasket.

You can check this by pulling the airhorn. There are two cavities behind the secondaries, if they have fuel in them then the fuel is bypassing the gasket. While you have the airhorn off, check the float level as too much fuel pressure will bend the little tang that contacts the float needle which in turn affects the float level. I hope this helps you.

Good luck,
Click to expand...
 
Another thing to check. As mentioned, Carter style carburetors cannot take the same pressure that a Holley can. In the picture below, the two red circles are where the float bowl vents are. After a WOT run, hop out and look to see if there is wet fuel around those openings. This would indicate the float bowl being overcome with fuel pressure and being pushed out of the vents. It would also explain why you're not seeing any leaks, because the excess fuel would be pulled right into the carburetor. You could possibly smell it, though.

EDELBROCK BOWL VENTS.jpg
 
This makes sense. I didnt think I had more than 5psi of fuel pressure but at hi rpm it must be more. Shall I check the wells where the secondary weights sit in for fuel? If this is correct than I would probablly adjust the float level a little lower and see what it does.
Regarda
Billy D...
 
Billbo said:
This makes sense. I didnt think I had more than 5psi of fuel pressure but at hi rpm it must be more. Shall I check the wells where the secondary weights sit in for fuel? If this is correct than I would probablly adjust the float level a little lower and see what it does.
Regarda
Billy D...
Click to expand...

I would check fuel pressure first. If there is too much, it will not matter where the floats are adjusted, they will be overcome regardless.
 
Is the rubber seal intact at the back of the hood?

If not engine bay vapors can be drawn into the interior via the cowl vent system.
 
I just checked the wells where the secondary weights sit in and it is wet with fuel. Obviously from the vents it drops into theses crevices. Ill see if I can get a regulator fitted. The Holley did not have this problem but this carb like said is more sensitive to pressure.
Regards
Billy D...
 
Billbo said:
I just checked the wells where the secondary weights sit in and it is wet with fuel. Obviously from the vents it drops into theses crevices. Ill see if I can get a regulator fitted. The Holley did not have this problem but this carb like said is more sensitive to pressure.
Regards
Billy D...
Click to expand...
Edelbrock has the instructions on how to check the float level and float drop at their web site if you no longer have that information. Also, don't cheap out
On buying one of them cheap (Mr Gasket) dial type pressure regulators. Get yourself an adjustable regulator with a pressure gauge.
 
I had the same issue once. Inconsistent smell of raw gas inside. Turned out it was a small leak, but it would evaporate off the intake surface after continuing to drive, so I never saw any loose fuel when I'd get it home. I found it by immediately pulling over and checking when I noticed the smell. Quick carb refresh and it was cured..stinkin accelerator pump diaphragm.
 
It's also possible he's smelling fuel from being rich at WOT and not having his trunk sealed up.
 
I just repaired a similar issue today. In the trunk is the vent line that goes from the filler neck thru the trunk floor (67 Dart). The tube on the filler neck and the tube that loops around and parallels the filler neck were not aligned properly and over the years had degraded till there was a gaping holes in the rubber cuppling tube.

20190901_161318.jpg


Every so often I would open the trunk and get a wiff of fuel. It's a convert with the top down so I don't know if it could be smelt in the cabin.

I aligned the tubes and replaced the old rubber cuppling tube, no more issue.

Not saying this is your issue but worth looking into.
 
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The Mr Gasket regulator is just a "dial a jet" device that has a bunch of graduated holes on a dial that you turn to choke down the fuel path cross section. You could do the same with a carb jet in the fuel line, or better: a 2-4psi Facet style electric pump. They work great on Edelbrocks that like to boil the gas out the bowls on hot shutdowns.
 
Hey rusty. All the dyno runs that I have seen, the fuel pressure starts to drop as rpm and load goes up. Pressure is at maximum at idle so to speak. I have checked for leaks and have checked the float level. Its got me baffled. I need to make sure a regulator may be the solution before I go out and buy one.
Regards
Billy D.
 
Its been my experience that most mechanical fuel pumps put out in excess of 5psi, probably closer to 9psi. Electric fuel pumps should have the psi indicated on its housing somewhere.

Eddy's like to operate in the 3.5-5psi range, anything more than that and you will have problems.

One reason why you don't want excessive fuel pressure with Eddy's is that the high fuel pressure puts constant pressure on that little tang you adjust the float level with and bends it, which in turn allows the float to rise and cause it to flood and overflow. An adjustable fuel regulator with gauge will control this.

Without it, you may adjust your float level today, but, tomorrow with the excessive pressure, you may have to go back in and adjust the float level again. Much like a dog chasing its tail. Ask me how I know.

Cheers!
 
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O.k. so basically you are saying running a Holley carb with a mechanical pump you dont see these problems because they are more resistant to higher fuel pressures?
Regards
Billy D.
 
Have you done the diagnosis I outlined? Gotten out immediately after a WOT run and LOOKED at the carburetor to see if it's wet around the bowl vents? Without diagnosis, you're pissin in a fan.
 
O.k. Rusty I will test it out in the next few days mate.
Regards
Billy D...
RustyRatRod said:
Have you done the diagnosis I outlined? Gotten out immediately after a WOT run and LOOKED at the carburetor to see if it's wet around the bowl vents? Without diagnosis, you're pissin in a fan.
Click to expand...
 
O.k I have installed a fuel regulator and fuel guage. Adjusted it to 4 p.s.i. All seems o.k. there seems to be no more gas smell so yes the pressure was high. I ckecked it before I installed the fuel regulator and yes revving the engine the pressure did go up to almost 7 p.s.i. I will monitor further more but the smell is no longer there .
Regards
Billy D...

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Thank you for the update. ( I want a right hand drive!!!!!)
 
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