what color are your spark plugs? are they wet or dry?
Hi there, thanks for this - I’ve ordered a new set of plugs so will be interesting to see then & I’ll let you know. I managed to find one set here on the uk on eBay to suit & they are Bosch Platinum 4236.
Also await the new carb mounting gasket from Rock Auto this week.
My latest notion that it might be worth tweaking the timing to suit the different fuel delivery of the newly rebuilt carb?
It ran fine before ...
Thanks for that - great resource to keep to handcheck your plugs from time to time. it will give you a good indication as to how your carburetor is functioning. here is a guide:
Know Your Engine - Read Your Spark Plugs
So I hope you guys don't mind me trying to get some info here. I have a 1966 Chrysler Newport 383 2bbl with a Bendix-Stromberg WWC Carburetor. I just got the car a month ago and the car sputters and occasionally back fires through the carb. I have ordered a rebuild kit. I worked on these cars 40 years ago, but have not touched a carb in 35 years or so. Any advice???In general, not a lot to go wrong with those carbs. Set the idle mixture, starting at 1.5 turns outward on the idle mixture screws, with a hot idle rpm of about 600rpm or so, as I recall.
Make sure the base plate nuts are snugged-down nicely.
As far as the cold starting issues, when the engine is cold, make sure the automatic choke flap closes fully, then is pulled open a bit as the engine starts by the choke pull-off diaphragm. With the engine cold and everything at an ambient air temp of 70 degrees F, the choke flap should just close, easily and gently, if it's got more "pressure" than that, then the choke thermostat in the intake manifold probably needs to be backed-off a notch or two. With age, those thermostatic springe tighten-up, so if you set it to factory specs, or it is still at factory specs, it'll not let the choke open soon enough to not over-choke the engine.
Back when the cars were newer and we still had leaded fuels, it was common to see the light gray coloring at the end of the exhaust pipes. Which indicated a normal carb mixture situation. BUT when the lead left, the pipes would color "black" and fluffy, typically. As my '77 Camaro did when it was new. So, what you might perceive is a too-rich mixture, from the rear pipe coloring, might be completely normal for unleaded gasoline (ethanol'd or not).
A better check might be to look at the spark plugs instead.
But do ensure that the hot base idle timing is correct for the car. That the idle mixture is set to specs. That the spark plugs are gapped correctly and reasonably clean, as to accumulation or deposits on the insulator and ground electrode.
Also look for vacuum leaks, including the vacuum advance can.
You can set the accel pump arm in the long slot for a bit longer accel pump shot, but generally, the center slot will work just as well, from my own experiences in seeking a bit more performance on out '66 Newport 383 2bbl when it was new (and I was in high school).
Do the carb "kit" AFTER you've done everything else to make sure things are adjusted right and such. By observation, unless the innards are really gunked-up, the carb "kit" deal gave us more peace-of-mind that all was well, with little improvement in performance, if any at all, back then.
It will not hurt to spray the carb with a good carb cleaner, in the venture area and on the outside. When we'd get the '66 Newport tuned-up at the local Chrysler dealer, back then, the tech would get a can of solvent and splash it around onto and into the carb. "Solvize" is what they termed it. This would easily wash the accumulated varnish and such off of the carb venturis and clean up the choke flap to make sure it was free to move.
DO also make sure those well plugs in the bottom are tight and do not leak. They plug passages which go to the float bowl, so when they leak, it can get "firey" under there. On some, which use a staked-in ball bearing surrounded by a sealing solder, modern ethanol'd fuels degrade the solder and the balls can fall out. Not good! Just spray everything down to get it clean and watch that area, for good measure.
Just some thoughts,
CBODY67