I scanned all through here. From what I see, you have an edelbrock carb, and you have tried everything except the carb? I believe you have some carb issues, and possibly some vacuum leak or loss.
I've been watching this thread for awhile. Seems like it isn't going anywhere. I'm not really clear on what the problem is. I'm going to go out on a limb, and say it sounds to me like the engine is momentarily cutting out for a split second or so. I would look at the battery connections, and the connections at the starter. Make sure everything is clean and tight. Then, I would look at the ignition lock cylinder and ignition switch. See if you can play with them and the wiring to see if that is what's causing the cut out. When you name the thread engine stumble at idle, it suggests hesitation when transitioning from in gear idle to off idle. That may be a separate issue, or not.
I know the battery and starter connections are all good i will look into the ignition side and the electrical end of it also this car was hacked apart by the previuos owner it has a lot of make shift stuff going on with it i have to sort out I will let everyone know what i find if anything
Electrical all seems good not really sure how to adjust a accelerator pump shot some people have mentioned still at a stand still changing out cap and rotor today when i get home but the one in there looks good ---------- Post added at 08:22 AM ---------- Previous post was at 08:21 AM ---------- also the car seems to be lacking power ---------- Post added at 08:22 AM ---------- Previous post was at 08:22 AM ----------
I suggest you swap out that edelbrock carb, it is very likely the cause of all your trouble. The 350 will never run right witht hat carb on there.
Get it idling, and start spraying carb cleaner near the throttle linkage on the primary barrels, you could have a vacuum leak somewhere that's leaning out your mix.
I was searching for something else carb related online and I found a post that made me think of your issue. http://www.chevytalk.org/fusionbb/showtopic.php?tid/217238/ "Edelbrock has never manufactured carbs. They are all either Rochester or Carter cores. They rebuild them and install performance modifications to them and thats all. Traditionally, but with a few exceptions, Rochesters came on GM, Carters on Chrysler and Hollys on Ford. Rochesters are good carbs. They got a reputation and a nickname of "quadra-bog" by people that didn't know how to tune them. They are a "spread-bore design where the primaries are smaller than the secondaries. Fuel efficient at cruse and all the fuel you need when you step into it. The reason they bog is when the secondary air door is out of adjustment. Steve" 72novaproject
I know you replaced spark plugs but i would like to know with what brand plug and what did you gap them at?? Also, are you running a stock distributor or HEI ? Please let me know, Thanks
Mallory dist. part # 4764301H with 2092m cap and rotor Mallory 6100M High Performance E-Spark Replacement Module Mallory 29351 High Performance Active Power Filter Mallory 700 High Performance Ballast Resistor Mallory 938 8mm wire kit Bosch platinum plus 4009 plug gapped .060 http://www.taperformance.com/proddet...?prod=TA_1235P (carb and intake setup that came on the car when i bought it) 1975 350 head ID 1248452 F/30
I personally had the same problem you are having and i'll share with you how i corrected it. I took me a lot of time to figure out , but it worked. I got rid of the BOSCH spark plugs (they are made for european cars in my opinion) and put in AC R46 spark plugs and gapped them at .045 . It is an easy thing to do and it is a good baseline to start at. If needed, you could tweek the gap by .005 at a time. I have tried every spark plug made for that engine, and AC worked best for me. I am very curious to see if this helps you. Please let me know.
060 gap is pushing it in my opinion.... the 045 is more like the max anyways.....maybe with a magneto....
I would get rid of the pugs also., use the stock plugs for a 1970 engine. NGK plugs work good. What intake do you have on there? If it is stock get rid of the edelbrock carb and use a Q-Jet. The open adapter to make this carb work is the problem if it is a stock intake.
I still say that swapping to a Q jet will fix your issue... Those e-brock carbs NEVER run well on the 350.
I was telling a guy at the speed shop about my issue, he had me get a copy of the owners manual that has a trouble shoot guide, the guide is telling me to change the rod and jet size, he also told me about the problems with the ethenol fuel he has had with carbs and suggested starting with just the rods first and work from there. he ordered them for me today and should be in on monday he also said to get rid of the plugs and go with a smaller gap on the delco plugs i will let you all now what i find next week Sean I can't afford another carb at the moment need money for other repairs first, I think if i spend the time i can get this eddy dialed in right at least that's what i am hoping for ---------- Post added at 07:32 PM ---------- Previous post was at 07:26 PM ---------- The intake is a T/A performance stage one which they sell as a package with the 1406 edelbrock carb so i believe the guys at T/A wouldn't package the two together if they didn't work well together that is one of my main reasons for resisting a carb change coupled with the cost of getting a q-jet
Looking back at the posts in your thread, you seem to be describing two separate problems, and I don't believe that they are related. One problem relates to the title of this thread, engine stumble at idle. I take this to mean a miss at idle, like the engine stutters every so often at idle. I think that might just be the plugs or the gap, or both. The other problem you describe is when you mash the gas, the engine bogs and then goes. That is the carburetor. You are experiencing a bog because the secondaries are not coming in cleanly. But here's the problem with the Edelbrock carburetors that are modeled after the Carter AFB. They use a counter weighted secondary air valve. There is no way to adjust that air valve without taking it apart, and grinding on the counter weight, or adding more material to it. The Edelbrock and Carter AVS have an adjustable air valve. The tension is adjustable by increasing the spring tension, much like a Q-jet, but the Q-jet also has the primary vacuum break to slow the air valve down, and even that is adjustable. If a Q-jet is adjusted correctly, and calibrated correctly for the application, the transition from primary to secondary operation is seamless, and smooth. The primary side of the Q-jet is also much more efficient than any Edelbrock or Carter carburetor of this type. That isn't to say that some guys can't get this type of carburetor to work reasonably well on their engine. Sure TA Performance wouldn't sell you the carburetor if it wouldn't work with their intake, but I think if you asked them which carburetor they thought would be better for you, they would tell you that a properly calibrated and set up Q-jet was the better choice. In any case, you may be able to improve upon what you have by tuning it. You can adjust the metering, and the accelerator pump volume and rate, and that may get you improvement, but Like I said, there is no easy way to adjust the air valve, and that is a large part of your second problem IMHO.
