powerpigz-51. Place a thick gasket between the intake and the carb. Back in the day......I used a 1/4" gasket between my intake and the Holley.
Carb Boiling?
Thread Starter
Pro
Joined: May 2001
Posts: 683
Likes: 4
From: Laurens SC
Carb Boiling?
1984 converted to edlebrock carb. My car runs good but after driving it then letting it sit for about 10 minutes its harder to start- Flooded.
I checked it out- After about 10 minutes after I turn the car off, hood up, air cleaner off the pump jets shoot a healthy stream of gas into the intake all by themselves.
This puzzles me. I thought if the gas boiled, it would bubble up out of the vents on top of the carb and then fall into the carb throat. I would guess pressure builds up due to the heat and forces the gas through the jets just as if I had hit the throttle. It seems odd that it would squirt through the jets instead of out the top vents.
Is this normal for a boiling condition?
I lowered my float level a bit, installed new needles/seats and a FPR just to be sure there was no "over pressure" problems and that all seems good.
so again, is this normal for a boiling carb?
I checked it out- After about 10 minutes after I turn the car off, hood up, air cleaner off the pump jets shoot a healthy stream of gas into the intake all by themselves.
This puzzles me. I thought if the gas boiled, it would bubble up out of the vents on top of the carb and then fall into the carb throat. I would guess pressure builds up due to the heat and forces the gas through the jets just as if I had hit the throttle. It seems odd that it would squirt through the jets instead of out the top vents.
Is this normal for a boiling condition?
I lowered my float level a bit, installed new needles/seats and a FPR just to be sure there was no "over pressure" problems and that all seems good.
so again, is this normal for a boiling carb?
Instructor
Joined: May 2013
Posts: 248
Likes: 3
From: Central Minnesota
Are you sure its the jets and not the accelerator pump doing it? If you see fuel shooting out of the tiny brass tubes sticking out into the air flow above the venturis, that would be the accelerator pump. Most likely the "pump" is worn out and leaking when pressure in the carb builds after heat soaking. The accelerator pump itself is just a small rubber plunger, so that could easily fail, causing your problem.
Drifting
Joined: May 2006
Posts: 1,428
Likes: 7
From: Chewelah Wa
Heat soak is a common complaint with those carbs. You should have a thick insulating carb base gasket as a precaution. I have also heard that they are sensitive to too much fuel pressure, and they should be regulated to 5-6 psi. I am also pretty sure that there a lot of these running around with neither of these issues, but the gasket is a no brainer. Heat soak is one reason the Carter Thermoquad was made out of thermoplastic resin. (The Eddy's are Carter AFB copies)
Last edited by powerpigz-51; Jun 1, 2013 at 03:37 AM.
Drifting
Joined: Mar 2006
Posts: 1,263
Likes: 188
From: Wabasha Mn
Very common on a carbed 84 to have hot start problems. I use a 1/2" resin spacer but you can use 4 square bore gaskets stacked to ward off the heat. Hood clearance will be very tight with a 1/2" spacer. Mr. Gasket #97 heat shield may work too, is only 1/4" and has 3 gaskets and two heat shields.
Race Director
Joined: Oct 2000
Posts: 15,041
Likes: 79
From: central FL, near the beach.
good advice so far.
i added a 3" pc fan with dryer duct to cool air.
100% success. also has the 4 hole wood which delayed boil over to 1/2 to 1 hr without the fan.
surplus fans cost $3-6. don't leave home without one.
i added a 3" pc fan with dryer duct to cool air.
100% success. also has the 4 hole wood which delayed boil over to 1/2 to 1 hr without the fan.
surplus fans cost $3-6. don't leave home without one.
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Thread Starter
Pro
Joined: May 2001
Posts: 683
Likes: 4
From: Laurens SC
Thanks for the responses everyone. I assumed it was boiling because it happened after sitting a while. Read alot on the internet.
So then it IS normal for the gas to come from there under heat soak conditions.
My hood clearance right now is "0". I have 2 gaskets at the intake, then the Plate for my TV cable brackets (about 3/16 thick) and then another gasket before the carb is mounted. My aircleaner (triangle Edelbrock thing) already rubs the paint off the inside of the hood.
Yes its coming from the brass tubes- according to the diagram for the carb they are the "PUMP JETS"... In any case I can change the accelerator pump if it will help. It seems to pump a healthy stream when i need it to. The carb is fairly new, but I bought an entire rebuild kit to take the new needle and seats from (store didnt have the needle and seats separatly). I can change out the pump too.
This is actually my first Edelbrock... Worked on lots of Holleys, rochesters and some single barrel carters.. but this is my first experience with Boiling gas.
So then it IS normal for the gas to come from there under heat soak conditions.
My hood clearance right now is "0". I have 2 gaskets at the intake, then the Plate for my TV cable brackets (about 3/16 thick) and then another gasket before the carb is mounted. My aircleaner (triangle Edelbrock thing) already rubs the paint off the inside of the hood.
Are you sure its the jets and not the accelerator pump doing it? If you see fuel shooting out of the tiny brass tubes sticking out into the air flow above the venturis, that would be the accelerator pump. Most likely the "pump" is worn out and leaking when pressure in the carb builds after heat soaking. The accelerator pump itself is just a small rubber plunger, so that could easily fail, causing your problem.
This is actually my first Edelbrock... Worked on lots of Holleys, rochesters and some single barrel carters.. but this is my first experience with Boiling gas.
Thread Starter
Pro
Joined: May 2001
Posts: 683
Likes: 4
From: Laurens SC
Matt, can you post a picture of your settup? Is it permanently on the engine or do you put it on after running the car?
Race Director
Joined: Oct 2000
Posts: 15,041
Likes: 79
From: central FL, near the beach.
i have a switch under dash and a red LED. if i think i may be away 10+ minutes, i switch it on. sorry no pics of my 72 c3. All u do is go to home depot and pick out some dryer duct 3 or 4" whatever u can fit, and order a fan and switch.
try allelectronics.com Cat # CF-407 or CF-406 $4
duct to cool air, a-frame? under car? fenderwell?
zip tie, easy to install in 1 hr or so.
try allelectronics.com Cat # CF-407 or CF-406 $4
duct to cool air, a-frame? under car? fenderwell?
zip tie, easy to install in 1 hr or so.