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05-10-2006, 08:02 PM | #26 |
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Re: WIGDTW: need carb tuning advice
If you can keep it running long enough to keep spraying around you may find the vacuum leak. Also try and plug all ports on carb except the fuel inlet you can rehook these up later 1 at a time to try & locate the issue. You may also want to have a friend over and have them start it and look in the carb to make sure it's not flooding. Also assume when buying used that what your told and what is, is usually two different things. I've known guys selling rebuilt carbs to just spray them down with carb cleaner and say there rebuilt.
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1967 C10 - SWBSS Pro Street 427sbc, 700R4 & 4.10 Gears 1948 Chevy FleetMaster Coupe, LS1, (almost done) 1950 Chevy StyleLine Coupe 250/6 3x2 Dueces 2009 Toyota Tundra 1996 Harley RoadKing "I maybe getting old, but I can still burn rubber with the best of them" Last edited by Bowtie67; 05-10-2006 at 08:03 PM. |
05-12-2006, 01:11 AM | #27 | |
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Re: WIGDTW: need carb tuning advice
Quote:
Some part of your adapter setup is warped. This must be repaired before any other fix/tuning can be done.
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68 C10 250 4spd 69 C20 327 4spd 69 910 250 3spd 80 K10 350 4spd 76 C60 366 5spd school bus "THERE'S NOTHING YOU CAN BREAK THAT SOMEONE CAN'T BE PAID TO REPAIR" |
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05-12-2006, 01:23 AM | #28 | |
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Re: WIGDTW: need carb tuning advice
Quote:
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68 C10 250 4spd 69 C20 327 4spd 69 910 250 3spd 80 K10 350 4spd 76 C60 366 5spd school bus "THERE'S NOTHING YOU CAN BREAK THAT SOMEONE CAN'T BE PAID TO REPAIR" |
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05-20-2006, 09:16 PM | #29 |
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Location: Just outside Durham, NC
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Re: WIGDTW: need carb tuning advice
ok, an update to all of you following this thread.
I contacted the guy I bought the carb from, he said it sounded like there might be debris in the needle and seat, so he suggested I pull that out and blow it out with compressed air, in the opposite direction from how the fuel runs through it, so I pulled it, hit it with carb cleaner and blew it out with compressed air. I had some people express that they felt somehow the inline filter might be an issue of some sort, so I replaced the line from the fuel pump to the carb with a single line with no filter. Tonight I finally had a helper, so I was able to have her start the truck while I was under the hood. The truck will fire and idle for 2 or 3 secs. with two pumps of the gas, then it does. I disconnected the throttle linkage and tried to work it manuall while my helper turn the truck over.....very slight pulls on the throttle made the engine rev. like crazy again, any attempt to keep it running with the throttle resulted in a backfire through the carb....it shot fire through the secondaries so I am back to the square one. To answer previous questions, the gaskets do not overlap to allow for a vaccum leak. Again, this engine ran perfectly before I installed this carb, the 1bbl allowed it to start and run without any issues.....I thought maybe I crossed some spark plug wires during the fuel line install.....but a double check showed they are all in the correct locations....IDEAS???? Would a vaccum leak really result in fire through the carb????
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1969 SS 350 Camaro Sold 2008 1970 3/4T K20, stock height with 33's, 250 I6, 3 on the tree, and locked front and rear 4.10's 1980 Chevy Malibu 2 dr Sold 2007 1993 Olds. Cutlass Ciera Wagon Traded 2006 2003 Saturn L200 w/5pd. D/D My list spans 5 decades with One common thread.....GM! |
05-20-2006, 09:30 PM | #30 |
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Location: Tallahassee Fl
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Re: WIGDTW: need carb tuning advice
Backfiring through the carb is a timing issue, usually. If it has a power valve in that carb, it might have popped that too, more bad news.
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05-21-2006, 11:29 AM | #31 |
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Re: WIGDTW: need carb tuning advice
Can you get a different carb to try? Backfiring thru the carb is a lean mixture, or a very out of time ignition. After reviewing all your pics, specially the one showing the rtv on the adapter/carb base and text, it seems that you bought someone elses problem. IMHO. Try a different known working carb.
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68 C10 250 4spd 69 C20 327 4spd 69 910 250 3spd 80 K10 350 4spd 76 C60 366 5spd school bus "THERE'S NOTHING YOU CAN BREAK THAT SOMEONE CAN'T BE PAID TO REPAIR" |
05-21-2006, 12:59 PM | #32 |
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Re: WIGDTW: need carb tuning advice
The RTV was on the intake, the carb was purchased seperately from a different individual. What is a good baseline to setup the mixture screws? Turn them until the bottom out, then back each out how many turns?
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1969 SS 350 Camaro Sold 2008 1970 3/4T K20, stock height with 33's, 250 I6, 3 on the tree, and locked front and rear 4.10's 1980 Chevy Malibu 2 dr Sold 2007 1993 Olds. Cutlass Ciera Wagon Traded 2006 2003 Saturn L200 w/5pd. D/D My list spans 5 decades with One common thread.....GM! |
05-23-2006, 08:56 PM | #33 |
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Location: Just outside Durham, NC
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Re: WIGDTW: need carb tuning advice
and the winner is......(insert drum roll)......Karl Hoh.....kinda.
The engine was back firing through the carb because it was too lean, but it was because the fuel pump was apparently too weak to keep the carb filled.....I primed it, but because it has no bowls, filling the fuel well only gave me about 10-15seconds of running at idle.....when i turned up the idle screw to try and keep it running, it would suck down that fuel in seconds. Also, while filling the fuel well the fifth or sixth time I spilled some raw fuel down the carb and found what was likely the primary vaccum leak at the base of the middle intake runner.....tightened that up, replaced the fuel pump with a new one....and she fired right up! p.s. open headers on an I6 sounds SURPRISINGLY awesome! Still have some issues to work out, but I will post those in a follow up thread. Thanks to everyone who tried to help!
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1969 SS 350 Camaro Sold 2008 1970 3/4T K20, stock height with 33's, 250 I6, 3 on the tree, and locked front and rear 4.10's 1980 Chevy Malibu 2 dr Sold 2007 1993 Olds. Cutlass Ciera Wagon Traded 2006 2003 Saturn L200 w/5pd. D/D My list spans 5 decades with One common thread.....GM! |
05-23-2006, 10:51 PM | #34 |
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Join Date: Feb 2006
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Re: WIGDTW: need carb tuning advice
When you know it worked fine before something was changed, the battle is to figure out what is wrong. I'm happy that you have it running.
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68 C10 250 4spd 69 C20 327 4spd 69 910 250 3spd 80 K10 350 4spd 76 C60 366 5spd school bus "THERE'S NOTHING YOU CAN BREAK THAT SOMEONE CAN'T BE PAID TO REPAIR" |
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