Carburetor problem??

foxbodymike87

Active Member

Jul 12, 2011

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Nov 14, 2011

#1

• Nov 14, 2011

• #1

so i was driving around in an 85 k10 that has a 350 with aluminum heads, cam and holly carb...after driving around i would slow down or stop and then when i would hit the gas the truck would bog then pick up again..it did every time i stopped and it actually stalled one time. could this be a carb problem??

 

Stever89

5 Year Member

Dec 14, 2009

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Biloxi, MS

Nov 15, 2011

#2

• Nov 15, 2011

• #2

foxbodymike87 said:

so i was driving around in an 85 k10 that has a 350 with aluminum heads, cam and holly carb...after driving around i would slow down or stop and then when i would hit the gas the truck would bog then pick up again..it did every time i stopped and it actually stalled one time. could this be a carb problem??

Click to expand...

If it is, it's most likely the accelerator pump.

 

LarsD

Founding Member

Jul 2, 2002

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Texas

Nov 15, 2011

#3

• Nov 15, 2011

• #3

Could be going slightly lean as well. The new Holley on my truck did this. If it does it in neutral, then jam on the gas and be ready to tap the accel pump arm when it stumbles. If it gets better, then you might try swapping out pump cams for one that richens it up a little more.

 

BlackGT89

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Dec 16, 2002

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Huntsville, AL

Nov 15, 2011

#4

• Nov 15, 2011

• #4

Brings back a lot of bad memories about carburetors... It could be as simple as the idle screw or idle mixture needing adjustment or it could be as drastic as needing a complete rebuild. Are you putting out a lot of black smoke (running rich) ? I discovered on one of my Holley carbs that the back barrels were creeping open a bit at idle and dumping way too much fuel down the engine. If you've had a few backfires you might have blown the power valve in the carb (supposedly they have a new design nowdays ). Your floats could be hanging and dumping fuel (if they leak and start filling with fuel it's like pulling the lever on your toilet, it just dumps and dumps fuel). Could possibly have other leaks, some internal. If your fuel pressure is too high you could be blowing your needle right out of the seat and flooding the engine.

 

foxbodymike87

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Jul 12, 2011

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Nov 15, 2011

#5

• Nov 15, 2011

• #5

doesn't have smoke coming out at all..it starts perfect and idles perfect..im gunna ceck out the carb possibly tomarrow and see what i find.

 

BlackGT89

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Dec 16, 2002

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Huntsville, AL

Nov 16, 2011

#6

• Nov 16, 2011

• #6

I assumed it was running rich, so my bad. Probably is the accellerator pump as mentioned or could be the float level is set too low. A fuel pressure gauge could be a big help in sorting it out. Also if the gas line gets close to the exhaust at any point it could be purculating the fuel and causing vapor lock. Consider a phenolic spacer, or if you have one consider a thicker one if you have the room. Also consider a carb heat shield if you are convinced it is heat related.

 

foxbodymike87

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Jul 12, 2011

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Dec 11, 2011

#7

• Dec 11, 2011

• #7

changed the pump and still does it. Any other suggestions?

 

BlackGT89

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Dec 16, 2002

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Huntsville, AL

Dec 11, 2011

#8

• Dec 11, 2011

• #8

foxbodymike87 said:

changed the pump and still does it. Any other suggestions?

Click to expand...

Check the float level, might be set too low and could cause fuel starvation.
Might even want to pick up some clear float level plugs, but they get mixed reviews by some. http://www.shop.speedunlimited.com/p-2579-moroso-65226-holley-clear-fuel-bowl-sight-plugs.aspx

Edit: Keep a fire extinguisher handy too...

 

7991LXnSHO

wanna catch the space herp

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Sep 1, 2010

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Dec 12, 2011

#9

• Dec 12, 2011

• #9

DO NOT KEEP CLEAR SIGHT PLUGS IN! The heads popped off mine, left a swelled up part inside the peep holes, and were a pain to get out. They are a good diagnostic tool, but do use them long term.

Power valve or a vacuum leaks will be good places to look after float levels.

 

foxbodymike87

Active Member

Jul 12, 2011

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Dec 12, 2011

#10

• Dec 12, 2011

• #10

7991LXnSHO said:

DO NOT KEEP CLEAR SIGHT PLUGS IN! The heads popped off mine, left a swelled up part inside the peep holes, and were a pain to get out. They are a good diagnostic tool, but do use them long term.

Power valve or a vacuum leaks will be good places to look after float levels.

Click to expand...

Good to know. I've wondered why ppl put plugs in them. And i hada bunch of vacuum leaks that i fixed so i don't think thats it.