Location: Fort Lauderdale
Posts: 4,740
My VIN: 02613
Club(s): (DCF)
Per y'all's suggestions, I had a look in the fuel bowl. It's pretty nasty in there.
sediment1.jpg
sediment2.jpg
I'll check back in when I've cleaned it.
3.0L, automatic, carbureted
Location: Rochester, NY
Posts: 2,405
My VIN: 01049
I'd strongly consider taking the carb completely off the car and cleaning out all of the passages. Several times.
-Mike
My engine twists my frame.
1981 DeLorean, Carb LS4 swap completed
1999 Corvette, cam/headers/intake manifold, 400 rwhp
2005 Elise, stock
2016 Chevy Cruze
Location: Fort Lauderdale
Posts: 4,740
My VIN: 02613
Club(s): (DCF)
Gonna do that on Monday.
Also, considering that the spark plugs keep getting darker and darker, I wonder if some of the sediment I have seen may have prevented the power valve from closing all the way. So I'm going to flip the carb over and pull that out in the process of cleaning. (Or maybe just replace it - the whole kit is only $20.)
3.0L, automatic, carbureted
Location: Rochester, NY
Posts: 2,405
My VIN: 01049
Would you be comfortable with rebuilding the carb entirely?
-Mike
My engine twists my frame.
1981 DeLorean, Carb LS4 swap completed
1999 Corvette, cam/headers/intake manifold, 400 rwhp
2005 Elise, stock
2016 Chevy Cruze
Location: Rochester, NY
Posts: 2,405
My VIN: 01049
I'd go ahead and do it then. Shouldn't take more than an a few hours after a good overnight soak in some kind of cleaner.
-Mike
My engine twists my frame.
1981 DeLorean, Carb LS4 swap completed
1999 Corvette, cam/headers/intake manifold, 400 rwhp
2005 Elise, stock
2016 Chevy Cruze
Agreed. A few tips:
- keep an organized work area on a light colored surface (so that you can see any small parts).
- take your time
- lay out the parts and take notes on where they go and their orientation if you don't have a rebuild manual or a detailed video.
- use compressed air to ensure the passages are clean
- be surgically clean overall
-you can get couple spray cans of carberator cleaner for around $2 at Walmart or an Auto Parts store.
I rebuilt a couple carberators years ago ( not your model mind you...mine were a 750 cfm Rochester Quadrajet and a 650 cfm Holley "Double Pumper" ) and I found when they are rebuilt and adjusted correctly, they perform just like new.
Good luck with the job.
Last edited by DMC-81; 11-12-2018 at 10:45 PM.
Dana
1981 DeLorean DMC-12 (5 Speed, Gas Flap, Black Interior, Windshield Antenna, Dark Gray)
Restored as "mostly correct, but with flaws corrected". Pictures and comments of my restoration are in the albums section on my profile.
1985 Chevrolet Corvette, Z51, 4+3 manual
2006 Dodge Magnum R/T (D/D)
2010 Camaro SS (Transformers Edition)
Location: Florida: Pinellas County
Posts: 2,111
My VIN: 5003 Never placed Concourse
Club(s): (DCF)
You might also consider a new fuel filter before your next run. If this is the Motorcraft 5200 carb, I have a clean main body (bare) and possibly other parts for it if you want them-I'd be glad to ship them off to you, I have a variety of carbs that have been sitting on my shelf for years that I have no use for.
-----Dan B.
Location: Fort Lauderdale
Posts: 4,740
My VIN: 02613
Club(s): (DCF)
I already have a spare fuel filter. It's going to replace the one I pulled off of the carburetor today. When I tipped the fuel filter over, it became apparent to me that the filter is catching quite a lot of gunk (but obviously not all of it).
When I removed the power valve cover, fuel poured out. Looks like the vacuum diaphragm failed.
A leaky power valve sure could explain why I had such difficulty setting the idle mixture, why the engine smoothed out at high RPMs, and why I was getting awful fuel economy. It also explains why the spark plugs were getting darker and darker every time I looked at them.
A new power valve has arrived in the mail, but the gasket for the cover is part of the carburetor rebuild kit, which hasn't.
By the way: the power valve that I removed from the carburetor was stamped "7.5" for 7.5 inches of mercury. The replacement is supposed to be the same spec, but there's no number stamped on it. I guess I will just have to trust that it opens at the right vacuum...
3.0L, automatic, carbureted