Author Topic: flooding engine  (Read 4770 times)

bc69

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flooding engine
« on: August 01, 2010, 02:10:10 AM »
Having a problem after engine,(sb350) is good and hot, will not start after sets 5 min or so without crankkkkking foot to floor.
Have rebuilt the 4bl qjet. Covered all that I thought would be related to carb itself.
Thinking that it might be related to the heat from the exhaust crossover??

Any help out there on this?

I thought I had seen some discussion in the forum relating to this a short time back but can't find anything now.
Brad
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Petes L48

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Re: flooding engine
« Reply #1 on: August 01, 2010, 03:51:33 AM »
This may be what you're looking for

http://camaros.org/forum/index.php?topic=1359.0


bc69

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Re: flooding engine
« Reply #2 on: August 02, 2010, 02:16:44 AM »
Bingo! I thought I had seen something before. Thanks. I hope this cures my problem. Sounds that it needs done anyway.

Think GM will still honor the recall?  Ha!
Brad
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Oregonjam

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Re: flooding engine
« Reply #3 on: August 04, 2010, 03:57:56 AM »
Also check to be sure no heater hoses are contacting the fuel line. If so add the factory style strap to the fender well and make sure the hoses are the factory length to avoid contact. The heat transfer from the hoses to the fuel line can assist in problems. The heat shield definitely needs to be in place below the carb as well.
68 07D SS350
John

mikefam

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Re: flooding engine
« Reply #4 on: August 04, 2010, 11:00:04 AM »
It could be that the plugs in the bottom of the Qjet body are leaking.
Take a look at this link:

http://www.mre-books.com/quadrajet/carbrebuild.html

Mike.
68 Convertible w/327 275hp donor engine from a 67 Impala and TH350

Petes L48

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Re: flooding engine
« Reply #5 on: August 04, 2010, 02:46:32 PM »
Just recalled there was also a similar discussion about that intake heat passage, which details the correct carb gasket/heat shield order.  Looks like it is often mistaken:

http://camaros.org/forum/index.php?PHPSESSID=49a4hehdh51t3gnnn9843imla3&topic=278.msg8994#msg8994

Oregonjam

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Re: flooding engine
« Reply #6 on: August 06, 2010, 03:34:33 PM »
I have also run into leaking fuel from the bowls as described by the link mikefam has posted. This was definitely an issue on most early quads I  have worked on. However typically this would be demonstrated by an immediate turnover and then no fuel for an extended period of trying to start. This will take to too empty the bowls into the intake and typically was a problem for starting until hours of sitting if the leak was exceptionally bad. If the car was already run that day I would find it difficult to believe that five minutes would be enough time for this to happen. If it sat for  over 4 hours it may be an issue. I think this is heat related.

If you start the car and shut it off before reaching operating temp but it starts right away again it is probably related to heat.
I'm betting that it is related to the crossover or other vapor lock issue.

BC69- let us know what you find.   
68 07D SS350
John

bc69

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Re: flooding engine
« Reply #7 on: August 11, 2010, 04:18:52 AM »
Have plugged the hot-slot. Maybe slight improvement.
Fuel line runs behind the alternator close to block. May try to move it outside around alt.
Morning after pulled carb and found gas in manifold.? Came from somewhere.
Noticed that plug on right of filter housing front-to-back getting damp, leaking slightly, so... think maybe wells leaking too!
Brad
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bc69

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Re: flooding engine
« Reply #8 on: August 11, 2010, 04:22:33 AM »
Can Qjet off BB 396 be used on SB 350 ?
Brad
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tmodel66

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Re: flooding engine
« Reply #9 on: August 11, 2010, 11:48:48 AM »
Yes it's just got bigger jets and a little different setup.
Daniel  
'69 SS 350/4 speed  Fathom Green--POP

bc69

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Re: flooding engine
« Reply #10 on: August 12, 2010, 02:25:36 AM »
Possible to use the jets and rods off SB and set up like SB?
Brad
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My68SS

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Re: flooding engine
« Reply #11 on: August 12, 2010, 06:33:43 AM »
Possible to use the jets and rods off SB and set up like SB?
For sure. Swap primary jets and rods complete with rod plunger and spring, secondary rods and hanger, accelerator pump and you should be good to go.
Also, when the engine is idling, check that there is a small amount of clearance between the choke pull-off rod and secondary air valve arm.
When the secondary throttle plates are opened, the air valves need to immediately snap open a small amount to expose the secondary pullover bleed holes to manifold vacuum.
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

Stingr69

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Re: flooding engine
« Reply #12 on: September 07, 2010, 09:06:11 AM »
Do you still have the fuel return line from the filter functioning? Just a thought.

You can check for leaking well plugs by starting it up cold, shut it down, and clamp the fuel line with a vise grip. Wait for a few hours and see if you still get gas dripping into the manifold. Lots of people worry about the well plugs but heat is a culprit more often IMHO.

-Mark.

mikefam

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Re: flooding engine
« Reply #13 on: September 07, 2010, 11:31:54 PM »
What are you guys using to plug the heat ports in the intake manifold?

Mike.
68 Convertible w/327 275hp donor engine from a 67 Impala and TH350

tmodel66

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Re: flooding engine
« Reply #14 on: September 08, 2010, 12:24:56 AM »
I used oil galley plugs. Any parts house should have'em.
Daniel  
'69 SS 350/4 speed  Fathom Green--POP