Slant Six Forum :: Won't idle/keep running

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Won't idle/keep running https://slantsix.org/forum/viewtopic.php?t=60078	Page 1 of 2

Author:	Wesola78 [ Thu Aug 25, 2016 7:53 am ]
Post subject:	Won't idle/keep running
Okay, this is on my '78 Volare.with 225 and a 904 automatic. I recently (about two weeks ago) removed the Weber carb and Offy intake and replaced them with a factory super six intake and good used Carter bbd. At the same time, I swapped out the modified rear exhaust manifold with no intake heat and installed a modified rear exhaust manifold with intake heat. It was running fine, but I did have a slight exhaust leak. This went away after I tightened the nuts on the exhaust pipe. It was.running fine after this. Then yesterday I changed the oil. 10w-40 and 1 Lucas oil stabilizer. Now the engine will start right up, and when I'm cruising, it runs fine. However, it will not keep running when I stop at a red light, or even in park for very long, unless I keep giving it gas. It wasn't doing this until after I changed the oil. Could it be the thicker oil? Or something else? I just changed the spark plugs, no real difference. I'm thinking fuel delivery, or what? I have the day off from work today, so I have some time to work on it. Any helpful suggestions will be appreciated. Thanks!!!

Author:	slantzilla [ Thu Aug 25, 2016 8:43 am ]
Post subject:	Re: Won't idle/keep running
Quote: good used Carter bbd. Classic symptom of worn throttle shaft bushings. I would guess the oil change was just coincidental.

Author:	Dart270 [ Thu Aug 25, 2016 8:54 am ]
Post subject:
I once put on a BBD and it worked great for a about 1-2 days of driving around, then the idle deteriorated severely. Must have worked loose the gunk that was sealing up the throttle shaft... Lou

Author:	Wesola78 [ Thu Aug 25, 2016 8:55 am ]
Post subject:
Dennis, Thanks for the reply. So, I need another carb? Hmm...

Author:	Joshie225 [ Thu Aug 25, 2016 8:56 am ]
Post subject:
BTW, Lucas Oil Stabilizer is nothing more than heavy oil without any additives and as such it dilutes the additive pack in your oil. It certainly doesn't contain anything that "stabilizes". A good XW-30 should do fine if the engine isn't whipped. If you need a 10W-40 then use a High Mileage 14W-40. The 10W-40 with Lucas is probably in the 20W-50 range and you'd be better off using 20W-50 as you'd at least have a full strength additive package.

Author:	Wesola78 [ Thu Aug 25, 2016 9:11 am ]
Post subject:
Thanks Josh! I have known for a while that this slant is getting worn. Smoke coming from the breather, and out the tailpipe. However, since I changed the oil, its not smoking out the tailpipe. It really is time for another slant/rebuild, I just wanted a good bbd and intake heat before I did that.

Author:	SlantSixDan [ Thu Aug 25, 2016 9:34 am ]
Post subject:	Re: Won't idle/keep running
Quote: yesterday I changed the oil. 10w-40 and 1 Lucas oil stabilizer. That's at least one poor choice. Oil does not need to be "stabilized". At best, this stuff is a waste of money. At worst, it threatens your engine's health. The Lucas people are notorious liars. See here. If your engine is a tired pony (and it sounds like yours is getting that way) then heavy oil can wring a few more miles out of it. But at that point just use SAE30 or 20W50, minus any "stabilizer" or other additives. That said, the contents of your crankcase probably aren't causing your idle issue (though if your engine could talk, it would probably be saying "Get this snot out of my crankcase, please!"). The appearance of the problem is probably coincidental, but the first thing to look for is vacuum hoses knocked off their ports. Also check for a stuck-open or faulty PCV valve, and make sure the EGR valve (if it is still present) is hooked up properly and isn't stuck open. Once those checks are done, then try readjusting the idle mixture. If that doesn't do it, proceed as described here and give the PCV valve a shot at the same time. (Your idle issue probably is not being caused by a sloppy throttle shaft; it would have to have slop measured in fractions of an inch (not thousandths) before it could admit enough air to stall the engine.)

Author:	slantzilla [ Thu Aug 25, 2016 9:34 am ]
Post subject:
Your best bet is to find an old time carb shop that can rebush the plate. It's not cheap, but most of the rebuilt carbs you can buy will have the same issue. Not sure if they are still around, but A&G in Oak Park, Il did one for me many years ago. It worked flawlessly when I got it back.

Author:	Wesola78 [ Thu Aug 25, 2016 9:41 am ]
Post subject:
Thanks Lou! And thanks Dan! No EGR, but I will recheck the vacuum hoses. I will also check the PCV. By the way Dan, and everybody else, I think I have learned the hard way about the importance of intake manifold heat.

Author:	Reed [ Thu Aug 25, 2016 12:36 pm ]
Post subject:
Wes- You have a PM. Also, if you are considering getting a brand new carb, check these guys out: http://www.nationalcarburetors.com/look ... num=nd2559

Author:	Wesola78 [ Thu Aug 25, 2016 4:26 pm ]
Post subject:
I tried spraying it with carb cleaner (berryman), removing the idle screws and spraying in there, but to no avail. I have thought about going back with the Weber, but I would need an adapter for the super six manifold.

Author:	SlantSixDan [ Thu Aug 25, 2016 5:05 pm ]
Post subject:
What about the air bleeds, did you spray those out?

Author:	Wesola78 [ Thu Aug 25, 2016 5:39 pm ]
Post subject:
Yes, I did.

Author:	slantzilla [ Thu Aug 25, 2016 6:12 pm ]
Post subject:
With it running spray carb cleaner at the throttle shaft on both sides. Also, wiggle it around and see if the idle changes.

Author:	Wesola78 [ Fri Aug 26, 2016 8:43 am ]
Post subject:
Hmm, when I spray carb cleaner on the outside of the carb, the idle goes up. Last night I ordered an adapter to mount a Weber carb on a 2bbl intake. If I can't get this bbd or another one working, I'll reinstall the Weber. I'm a bit concerned with the throttle linkage, as the Weber will now be mounted facing a different way than before.

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