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#14508 07/26/2003 8:50 PM | Joined: May 2003 Posts: 111 Member | | Member Joined: May 2003 Posts: 111 | Ok Guys,
I'm trying to get my 68 p/u to run correctly. Timing is 4 btc, Idle 680. Electronic ignition. (oh yeah, 250 CID with 1 brl, 4spd manual). Plenty of power, mileage 11mpg (yuk).
So why does she diesel when I shut her down? No leak at manifold, or Carb. I've tried to advance the timing, to 6 and 8 btc, engine runs smoother, still diesels.
35 + years of rollin' steel!
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#14509 07/26/2003 9:15 PM | Joined: Jul 2002 Posts: 385 'Bolter | | 'Bolter Joined: Jul 2002 Posts: 385 | Your poor fuel economy may be a clue. Dieseling is sometimes caused by fuel draining out of the carb after shutdown. When the engine is hot it doesn't need spark to ignite fuel that dribbled into the combustion chambers. Does the throttle plate close completely when you shut it down? Is the choke functioning correctly? | | |
#14510 07/26/2003 11:02 PM | Joined: May 2003 Posts: 111 Member | | Member Joined: May 2003 Posts: 111 | Good point Hedgehog. I'll check into the carb. I know I've cleaned the outside to a purdy shine (ok, less dingy) and the linkage seem to be smooth. Choke is disconnected at the moment and open since I need a new cable. In this heat I don't need it much.
Thanks
35 + years of rollin' steel!
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#14511 07/27/2003 11:07 AM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | Try turning down you idle speed as low as it will run, maybe 450 rpm. | | |
#14512 07/27/2003 3:40 PM | Joined: Apr 2002 Posts: 146 Wrench Fetcher | | Wrench Fetcher Joined: Apr 2002 Posts: 146 | The problem is the "stuf" they sell as gasoline today. Try a higher grade of fuel.
if it dosen't need fixed, break it
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#14513 07/27/2003 10:01 PM | Joined: Feb 2001 Posts: 1,096 'Bolter | | 'Bolter Joined: Feb 2001 Posts: 1,096 | I had a '70 Buick Skylark conv. with the 350 in it. It also did that running on thing , I traced it to the throttle not closing off properly when the eng. was shut down.
On that engine there was a device (vaccuum or electric, I dont remember) that pulled the throttle properly closed when the eng was shutoff , it was faulty.
Temporary fix was to adjust the idle setting . | | |
#14514 07/30/2003 6:59 PM | Joined: Jan 2001 Posts: 198 Member | | Member Joined: Jan 2001 Posts: 198 | Another thing that can cause run on is carbon build up on the tops of the pistons, and engine temp. | | |
#14515 07/30/2003 10:20 PM | Joined: Oct 2001 Posts: 3,458 Extreme Gabster | | Extreme Gabster Joined: Oct 2001 Posts: 3,458 | I bet your power valve in the carb is stuck open. That will dribble in extra fuel and give you terrible economy but won't affect power.
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