Throttle bog..

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Dogdish95 said:
It happens in drive around 2000 rpm’s. In second gear I mash the pedal %80 to the floor and it’s accelerating nice and quick. I go to %100 foot to the floor I get the stumble like it’s out of gas (rough idle and ping then engine shuts off unless I lift off the gas) and it will go no faster or move other then the momentum it has already picked up. I then lift my foot off the gas back to %80 or lower and as I am lifting (decelerating) it picks up speed as if it was to the floor. It doesn’t matter how long I have my foot to the floor or how much I push the pedal down it does this. In each gear as well as idle.
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Try road testing with the fuel cap loose or removed. Just don't make any quick/hard right turns.
 
I was having a bog when I mashed it , it was leaking valve seal , my intake valves where all cartooned up
sent it back to the head shop and and they knurled the guides and put better seas on.
timing chain loose would be a easy thing to check also.
 
"a" leaking valve seal won't cause a bog in any way that I can think of..... on guide knurling, I've seen it done, many times but given the less than stock surface area you have in the guides now to actually "guide the valve" and what you do have is raised/displaced much like cutting threads, it is a "weaker" repair than just reaming a little more oversized so they can press a real guide into place. so what Im saying is it'll be OK for a while but won't last as long as putting in a replacement guide.
 
I had a v8 that did this. It was the vacuum advance plate gummed up. Make sure your accelerator pump is 100% working too. Iirc the 1920 had a weird pump setup.
 
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I've never seen a cartooned up intake valve.
 
volaredon said:
"a" leaking valve seal won't cause a bog in any way that I can think of..... on guide knurling, I've seen it done, many times but given the less than stock surface area you have in the guides now to actually "guide the valve" and what you do have is raised/displaced much like cutting threads, it is a "weaker" repair than just reaming a little more oversized so they can press a real guide into place. so what Im saying is it'll be OK for a while but won't last as long as putting in a replacement guide.
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it wasn't the seal the problem , it was the oil/carbon that was baked on the intake valve that was soaking up the gas and causing a bog. stumble. back in the day the fire had that issue and the gm tab was remove the injectors and blast the carbon off with coconut sand of some sort
 
I have a feeling this thread is going to get animated.....:D......:rolleyes:
 
rotate the distributor a few degrees and try it again. Itll idle great over a wide range of advance.
 
Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Tune-up parts and technique suggestions in this post.
 
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