Author Topic: odd burble sound - can you help me figure out what that means?  (Read 2687 times)

Offline wcumagic

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odd burble sound - can you help me figure out what that means?
« on: November 11, 2012, 12:27:06 PM »
Alrighty, my wife drove the car the other night and said it was spittin and sputterin all over the place and hard to start, and when I checked it that night, the upper gasket was wet and it looked like some fuel had spilled out the top.  Today I took the air horn off and lowered the float level (It LOOKED like just a hair over 1/4 inch before) to just a hair under 1/4 inch. 

Took it for a test drive, and at full throttle it ran like stink, but at 1/2 to 5/8 or so throttle (I reckon before the secondaries opened up) at the same time as the regular throttle noise, I noticed a burble, burble sound that I was unfamiliar with.  ALMOST like it was missing, but not quite.  I dont think it was stumbling, but that noise worried me.  Is that indicating a lean or rich condition, or have I not lowered the float level enough?  (upper gasket is still wet)

oh, its a 17056259 on a modified (was throwing 9" of vacuum with old holley carb) mopar 340.

Its still kinda hard to start now, but I may just not have this carb figured out yet on this engine (on my old camaro I had, if you did not pump twice exactly, it would be a bear to start  :P ).   

Thanks for all the ideas I hope to get!    ::)

Offline wcumagic

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Re: odd burble sound - can you help me figure out what that means?
« Reply #1 on: November 11, 2012, 12:34:34 PM »
idle screws have very little bearing on idle vacuum until they are almost closed.  I've got them set now at 1 turn out. 

Its also throwing 11" vacuum with this carb (go figure!  :o )

Offline wcumagic

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Re: odd burble sound - can you help me figure out what that means?
« Reply #2 on: November 11, 2012, 01:50:03 PM »
Timing is set at 10 degrees, but she backfired on me once when I drove it again a minute ago.  Too much fuel?  what gives?

Also the "burble, burble" is all the way through the rpm band, from mid on up to full blast.  when it does that "burble" it does not build power when it happens.  in other words, if you can imagine a torque curve going up through the rpms, I would imagine it flattens out when the burble happens, then continues up.
« Last Edit: November 11, 2012, 01:55:01 PM by wcumagic »

Offline Cliff Ruggles

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Re: odd burble sound - can you help me figure out what that means?
« Reply #3 on: November 13, 2012, 02:30:58 AM »
Did you convert the carb to electric choke?  That is a hot air choke model from what I can remember.

The float setting of 1/4" is fine. 

Not sure about the burbling sound?  Don't have a lobe going bad on the camshaft?  Any problems with an intake valve, spring, or cam lobe will cause a similiar condition......Cliff

Offline wcumagic

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Re: odd burble sound - can you help me figure out what that means?
« Reply #4 on: November 13, 2012, 01:31:46 PM »
I did block the hold into the carb from the hot air choke, but have not yet put an electric choke unit in it. 

I THINK I got it figured out talking to an old dude my dad knows.  He thinks I just didnt have the air horn tightened down enough so thats where my wet gasket came from.  I'm scared to strip them, so I didnt have them "goodntight" as some have suggested.   According to him, that MIGHT cause a vacuum leak after it warms up since it changes a little once it warms. 

I sure hope I dont have a cam going bad or anything like that - its virtually a newly rebuilt motor with about 600 miles on it.   BUT, I think I had a plug wire not connected well which may be my problem.  Gonna go test drive it again after the kids get done with their homework. 

Offline wcumagic

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Re: odd burble sound - can you help me figure out what that means?
« Reply #5 on: November 15, 2012, 04:24:57 PM »
Got the "burble" figured out.  It was a miss.  By and by, I replaced the plugs, and test drove it - still had the miss.  I pulled the dist cap off and looked in it, and the center electrode (?) was partly shattered and missing. Also one of the plug places on the top of the cap was blackened where the others were perfect.  That one plug wire had a resistance of .950 where the others were 0.  Threw a set of wires and a new cap at it and it fixed it. 

I'm just darn glad it wasnt internal!

now I just have to figure out finer settings !  Thanks !