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Engine bogs when floored

After doing some reading here's what I've found ; acc. pump nozzles are pressed into the carb body [non replaceable] acc pump linkage can not be altered , Your problem is most likely mis adjusted sec. carb flap adj [not closing completely]Google " THECARBURETORSHOPP LLC for some good reading......that's a "smallish" cam so should be easy to tune....AGAIN , call the guy who built the carbs , if anyone knows, he does...
 
FWIW my 388 stroker w/2x4 tunnel ram w/ similar gearing to yours avg.'s 16.5 mpg which tells me you're runnig rich internal leak ...flaps not closing ????
 
Hey 2o2f, which carbs and manifold are you running? FWIW I couldn't find that cam grind in the Comp Cams catalog. Maybe a Summit house grind ?

J
 
edelbrock street tunnel ram w/2x450 holley [9776] 1:1 linkage , cam is 232-234 @ .050 - .490 lift . 10.2 :1 comp. - brodix ik200 heads

BTW , that mileage figure , I do not run a vacuum advance , so I'm leaving some mpg on the bench.....






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Something not mentioned by the OP, that also indicates a rich bog, is the lack of any popping back through the carbs, when it bogs. Most lean conditions I have addressed, this is a common occurrence.
 
Today I took a second look at the acc. pump and it does not seem to be putting out a lot of juice when activated. One side squirts more than the other and neither seem to be doing much. Tomorrow I will pull the plugs and check the pump. There is also a check ball that maybe stuck open causing gas to go back into the bowl instead of into the venturi. If the engine was running rich wouldn't the turnout be blacken? I'll know more tomorrow. My gas mileage is mostly running around city with some county road runs up to 55 mph.
 
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one finger john said:
Rubicon, this might seem odd, but does the kick-down on the trans work ? You know, passing gear ?
Also, from a stop, is the trans in 1st gear. On deceleration, does it kick down into 1st gear when it comes to a full stop?
3.70, 3.90, 4.11 gears might work better.
First things first. Call hotrodcarbs.com and find out wtf is happening. Find out what cam specs will work with you carb set up or get a low rise three carb manifold and send the tunnel ram back. Too much plenum volume. Or a swap meet four barrel, dual plane manifold with either a Holly or Edelbrock 750 cfm carb.

Or agree to pay me $1500.00 per week plus room and board plus business class air line tickets (round trip) to fly out to where you are and I will guarantee to get it to run properly.

John
Click to expand...
I put the trans in first then shift as I get going. I do it this way only when I'm jumping on it.. The trans work just fine down shifting and starting in first by its self. I do not have a kick down cable yet. Want to solve this problem before I change anything. I put the 4.11 gears in, it helped some but the exhaust was always screaming just cruezing so I went back to the 3.48 until I get the noise down to my liking.
 
I pulled the plugs and they were a little black around the edge of the plug. The electrodes were brownish tan in color. These are the original plugs when I first started running the engine. At the beginning, I was using 91octane no Ethanol. It was in the winter and I would start the engine up and let it run for awhile. At that time, it was running rich. After 500 miles I changed the oil and started using 93 octane with Ethanol and Joe Gibbs Carb Defender. I put in new plugs today and notice the old ones had a gap of .040". The plugs come set at .024" so the plugs were re-set to .040" by the engine builder. That's what I set them at. Right or Wrong. I took another look at the acc pump and when the throttle is activated, shouldn't there be a nice steady stream of gas shooting out? Its more like a half a squirt. I'm sure us old guys know about the half a squirt. My granddaughter is here so I don't have time to dig into the carb right now. On YouTube there is a guy that works on triple 2 set-ups for Pontiacs. "Mikes Carburetors" He talks about several things that could cause hesitation & bogging. Sounds like all he does is work on Carbs for a living.
 
Black around the rim = normal carbon [as long as it's "dry"] .040 sounds ok...light tan to white w/ethanol is good , dark tan to brown is rich , w/o being there it's impossible to comment on the pump shot ...
 
It should look something like the video. Fast forward to 4:30 in the video.

 
Black around the rim = normal carbon [as long as it's "dry"] .040 sounds ok...light tan to white w/ethanol is good , dark tan to brown is rich , w/o being there it's impossible to comment on the pump shot ...
 
Not sure what's going on, I see it just fine and it plays with no problem. Maybe this one will work.

 
If you can wipe the "black" off with your thumb or a shop rag you're o.k.
If there is no indication of oil burning a light grey dusting on the plug would be my liking.
Should have an a/f meter. You might be amazed.
Can you pull the accelerator pump nozzle and look for schmutz ? Little bitty schmutzes that could block the nozzles.
By the by, what plugs and heat range are you running ? Try running a standard mid range plug Occasional blasts don't constitute a need for a cooler heat range plug. Mostly just crusin'. Normal heat range plug.
I believe that MSD calls for .40 plug gap for their ignition system.
Yes, a nice, steady, constant, forceful steam as I remember. Same for the accelerator pump shot.

John
 
If one has a Dominator carb, yes that's how you adjust a Holly carb. Do we have anything in a rochester 2 barrel to illustrate how to adjust the accelerator pump shot ?

John
 
My carbs do not squirt like the video above. When I can, I will take apart the carbs to check the pumps. If they are not set up for Ethanol, they may have broke down by now. I will replace with new pumps. The are only $10 each. If that fixes the problem, it will be well worth the cost. Spanky, that's the guy I've watching.
 
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