I agree with Mike that a good carb guy is in order here. You need to find a mechanic over the age of 45, simply because almost all of the younger guys just don’t know their way around carburetors.
You guys know your stuff. It’s oil deposits. I’m holding a plug in my hand that looks just like the picture. Along with the gap bridging. Thanks
Using ac delco R-44
OK. Have you had the compression checked? If it’s low, it’s probably rings, if it’s OK, it might be valve guides and/or seals. You can replace seals without removing the heads.
I think the choke thermostat is adjustable, on the side of the carb is a round housing with set screws. If your choke is not fully open when warm loosen the set screws then rotate in whatever direction until the choke is fully open. It then can be adjusted on a cold morning to tweak it. the other alternative is to put in a manual choke control.
You can smell the fouled plug and many times determine if it is a rich or oil burning problem, Smells like gas gas problem, smells like fried oil, oil problem.
Not so fast guys. He has dry black deposits with gap bridging and even with new plugs in it he has to keep his foot on the pedal at idle or it shuts down. I’m not so sure we’re not still talking about fuel metering here. I’m not so sure it isn’t carbon deposition. I’m still thinking it’s a carb problem. I have a feeling that setting that carb up right will solve the problem. And he’s not using oil but going through a ton of gas.
I’m’ still wondering (a) if the idle stop solenoid was removed and the djustments messed with to try to stop the engine from shutting down at idle, and (b) if this is the original carb…or too big for the flow capabilities of the motor.
And, is the car new to you? Or has it been running well and this just started?
Or am I just being stubborn?
Nice link, Texases, by the way.
There are alot of good suggestions on here, but I dont see some important info…
Is this the original carb? Was the base gasket changed? I have seen many cars with different carbs that have vacuum ports plugged or leaving extra vacuum lines off of carb and they seem to run like what you are discribing… Also is this the 4 barrel or 2 barrel carb. 2 barrel carbs actually get worse gas mileage ans tend to run richer than 4 barrel. An aftermarket carb like edelbrocks with a good aftermarket intake may set you back about $600 plus gaskets and labor but are very good at fixing tuning issues…
Also if the basic engine is not sound no amount of tuning will keep it running smoothly for very long. have you had a compression test done? Also are the same 2 plugs usually clean?
I had a Edelbrock Performer on a 330 hp smallblock and never touched the mixture screws in 6 years. From experience I can recommend this carb (600 cfm with cam and manifold). Sold it when gas went to $4.00+ it was in a 1/2 pickup, got about 12mpg,hauled a**. I tried all those crazy plug designs,nothing changed for good or bad. It would ping bad on 87 octane, 9.3 ratio.
It has always done this since I’ve had it. there was a strong smell of fuel all the time until 2 barr carbo was rebuilt. I still smell fuel but it’s slight. Car isn’t using oil, just a bunch of gas, can’t tell if it’s orig carbo or not. I can take foot off pedal after car has warmed up and it runs well. If I don’t warm it up well, it will try and shut off and run crappy until I hold foot on pedal approx 30 secs and really floor it 2-3 times. It seems like something is clogged until It blows out by flooring it a couple times
haven’t had compreesion checked. wiil do
Since it’s a 2 barrel I’ll assume it’s original. Since it’s not running by itself when cold and loading up when warm I’m going to suggest starting with the choke control (the bimettalic spring), making sure that’s working and set properly, and then setting the meterng and idle from there.
I’m also still wondering if there’s an idle stop solenoid missing and someone perhaps cranked the idle screw up to keep the throttle plate open when idling and tried to adjust the mix to stop dieseling, or something like that.
Or perhaps the needle valve to the float bowl isn’t closing properly, or the float is sticking, causing too much fuel. That’d make it flood at idle unless you opened the throttle some.
Something ain’t right about this carb.
I wish I could get my hands on this. Id love to solve this one. I still suspect adjustments were made to try to compensate for things that fundamentally were not right.
There is one port located on front left side of carbo that is plugged. I will have a comp test done.