Hi everyone,
I just converted my 80 Dodge truck from a 1 bbl to a 2 bbl. It's running pretty good except sometimes when I switch it off it keeps wanting to run. This happens for only a few seconds then it makes a spitting sound and goes off. Any suggestions would be appreciated. Thanks, ole_blue

i think i read somewhere that the timing might be off.. not sure though, wait for someone to agree with me on this....

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70 Plymouth Valiant 4dr

I imagine carbon build-up is causing run on.

If the truck was running rich due to a mal-adjusted carb, lots of carbon can get built up. There are some tricks to 'steam' the carbon out by spraying small amounts of water into the carb while the engine is running.

Otherwise, if you have adjusted your new carb properly, some of the carbon should clear out with time and a little highway trip on a tank of premium seems to improve my truck's attitude.

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1980 Aspen 225 super six

Timing doesn't matter with the ignition turned off.

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1980 Aspen 225 super six

from the Haynes repair Manual

"21 - Engine continues to run after being turned off"

idle speed too high
ignition timing incorrect
incorrect spark plug heat range
vacuum leak
carbon build up - use cleaning solvent
valves sticking
egr not operating correctly
fuel shut off system no operating properly
overheating

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70 Plymouth Valiant 4dr

Yes, the Haynes manual might say it, but it's a non issue compared to the rest of the list.

I'm not attacking you, but I don't think ignition timing is the most common reason or indicated in this situation.

I would put it way at the end of the list with 'egr not operating correctly' .

Timing might be related to some of the other problems, such as 'idle speed too high' or 'overheating', but it is not the direct cause of run on, rather a factor leading to poor adjustment of everything else, such as 'vacuum leak'.

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1980 Aspen 225 super six

I think I am the Slanter with the less knowledge in this community, but I heard somewhere that when an engine "diesels", it also may be the need of a higher octane gasoline... just an opinion from the lesser of the lessers...

Ed

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My other car is... another DUSTER!!! .·.

we're all friends here ram!

no attacking,! i promise!

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70 Plymouth Valiant 4dr

You're not really trying to use a Haynes manual to actually get any useful work done, are you?

Here are instructions for how to use a Haynes manual.

Go get the Factory Service manual before you hurt yourself or damage your truck.

Dan, I am really surprised of the instructions on your link (good ones though )... is it really worthless as it says in the u225.torque.net site?. Some guys in here have told me that it is a good start.

As you know I am newby in all this, and the manual has been of great help for me... maybe it really shows my inexperience... So your advice to me as a novice is also to disregard what I've learned from the manual and get my brain washed... I do not want to play with the final warning on the instructions on that page... don't want to see my Slant destroyed.

Ed

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My other car is... another DUSTER!!! .·.

You're not [i]really[/i] trying to use a Haynes manual to actually get any useful work done, are you?

Lol, Haynes manuals are like comic books.

Jon, actually... I am , the thing here is that I am not a mechanic and have no technical training at all. I thought it was a good idea, I even planned to make the complete overhaul of the engine myself following the text.

Now I know...

Any advice on where to get real useful info on the matter, besides this great site?

Thanks,

Ed

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My other car is... another DUSTER!!! .·.

Ed: Good manuals are very easy to find in the US and Canada -- much harder in Mexico, so maybe someone cooperative up here can send one down for you. What year car/what type engine are you building?

Maybe I failed to mention that I had the engine tore down to the head, replacing the head, valve and intake/exhaust gaskets. I elimated the air pump which was corroded way beyond repair. I also elimated the vaccume amplifer and taped off the egr valve. The carb is a holley factory rebuilt carter 2425. It starts and runs fine, it just spits like holy hell (sometimes) when I switch it off. I checked the timing and at first it was set at 20, I backed it up to 12 at the moment. Thats the thing with me, I can make the slants run, just not well. I'll take some pics so you can get a better idea of what I've done so you can advise me better. Also I went with a manual choke If that halps in the diagonsis any. Thanks, ole_blue

What is a Holley 2425? Umm ... they did make a 2245 for V-8 engines.
Look at the throttle plates, do they have a hole drilled in each?
If so, this is probably admitting too much air (and fuel) when you turn off the engine, just like setting the idle speed too high.

Perhaps try soldering those holes shut when you use those V8 carbs on a slant 6.

There is a reason why those V8 carbs have the holes in the throttle plates, and it's not what is rumored here on this board from time to time, I have the real reason info here and will get it posted...... someday.