Dual Carb Problem need help |
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Dual Carb Problem need help |
Cazz |
Mar 17 2018, 12:38 PM
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#1
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Newbie Group: Members Posts: 13 Joined: 22-December 16 From: NC Member No.: 20,688 Region Association: None |
Any carb specialists out there? I need help with a carb problem.
-1974 2.0 with dual weber carbs -The car is spitting and popping out the carb on cylinders 1&2and also backfiring alittle. I've rebuilt the carbs and pulled this carb off again completely taking it apart and checking with no obvious issues found -With the car idling when I put my hand over each barrel on this carb there is no suction at all on my hand. The idle doesn't drop at all. Doesn't respond to any adjustments on the fuel/air mixture screws. -The carb is injecting fuel streams when I open the linkage by hand -On the carb on the opposite side when I put my hand over each velocity stack it really pulls air really hard on my hand and the car will bog down and shut off as it should. -I have new intake gaskets an new carb base gaskets installed. I sprayed carb cleaner around the base of the carb and also at the head with no change in idle. Any ideas? Is this car basically running on 2 cylinders? -On the opposite carb on cylinders |
r_towle |
Mar 20 2018, 09:21 PM
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#2
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Custom Member Group: Members Posts: 24,585 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Carbs are stupid simple.
They allow air into the engine, which is just an air pump. The fuel gets sucked in via the Venturi affect. So, carbs are NOT the OP real issue. He needs to make sure all four cylinders are pulling in the same amount of air. |
porschetub |
Mar 22 2018, 12:00 AM
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#3
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Advanced Member Group: Members Posts: 4,704 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Carbs are stupid simple. They allow air into the engine, which is just an air pump. The fuel gets sucked in via the Venturi affect. So, carbs are NOT the OP real issue. He needs to make sure all four cylinders are pulling in the same amount of air. SO well said Rich,op has gone to ground?no replies,never mind hope its all going in ? With the resources on here and the net for anyone to question why engine /timing and tune has anything to do with carb tuning amazes me (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) ,without all this being correct any work on carbs is a waste of time. Jeez its like ''groundhog day''....rant over and out. |
stugray |
Mar 22 2018, 01:07 PM
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#4
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Advanced Member Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
Carbs are stupid simple. They allow air into the engine, which is just an air pump. The fuel gets sucked in via the Venturi affect. So, carbs are NOT the OP real issue. He needs to make sure all four cylinders are pulling in the same amount of air. SO well said Rich,op has gone to ground?no replies,never mind hope its all going in ? With the resources on here and the net for anyone to question why engine /timing and tune has anything to do with carb tuning amazes me (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) ,without all this being correct any work on carbs is a waste of time. Jeez its like ''groundhog day''....rant over and out. Getting carbs right is ALSO an iterative process. You have to get it running first. Then you have to get it running good enough to perform the "Loping" idle test to get the idle adjustment screws set right (this is actually hard because it is a chicken/egg problem). This is often complicated by the conflicting requirement to break in a cam first thing BEFORE knowing if it is even running on all four. And you have to get it to run good enough to warm all the way up to properly set the valves, etc. etc. It is not possible to get everything perfect BEFORE getting everything perfect.... (IMG:style_emoticons/default/chair.gif) |
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