Tuning a 350 with Edelbrock Carb

[grandall1972]

Just picked up this 1984 Chevy K10 4x4 long bed with SM465 4 speed manual. It spent the better part of the last 20 years sitting in a garage. Having issues getting it to run correctly.

1 Fuel System is mostly new.
- Tank and sending unit are new
- Fuel pump is new
- Fuel filter is new
2. Cap, Rotor, plugs, and wires are all new
- Battery is new
3. Engine is good and was not put on until recently but had sat for a long time itself.
4. Timing is set at
- 12-13 at idle 700 RPMs
- 35-36 at 2500-2800 RPMs
- Both done with vacuum advance disconnected and capped

Believe it’s an Edelbrock 650cfm carb, very clean inside and out. Believe it had yellow springs and not sure on the jets. I followed the online instructions to set the idle and idle mixture screws. Have not messed with the high idle screw.

Truck starts up and idles great. Sitting in the driveway revs ok, but does stutter some. One the road It falls on its face and almost stalls at anything past 1/4 throttle.

Questions
1. Am I looking at a fuel or ignition problem?
2. Any chance it could be the ignition coil or module?
3. What do I need to do look at to get it tuned and running right?

Thanks in advanced for any help.

 

[jeep78]

The secondaries are likely mechanical. If they are opening too soon, would definately cause that.

A basic vacuum gauge and a multimeter will tell you a lot.

Could be lots of things, fuel is the likely culprit at this time. The ignition modules go out when hot, but they last a long time.

 

[barlowlc]

Sounds like a fuel delivery problem to me. If the truck has sat a very long time, the diaphragm in the fuel pump could be dried out... pump is obviously pumping if it’s running but it may not be able to keep up with the engines demand for fuel...maybe a fuel filter on the frame rail, near the carb, or maybe even in the inlet line for the carb could be gummed up... In my expierence an Edelbrock can be kind of finicky as well. When they are right they’re right...but man when they’re wrong...ugh Me personally, I always did better with a Holley.

 

[barlowlc]

Sorry, I see where your post says fuel pump is new...never mind scratch that

 

[barlowlc]

Have you had the top off of the carb?

 

[grandall1972]

Sounds like a fuel delivery problem to me. If the truck has sat a very long time, the diaphragm in the fuel pump could be dried out... pump is obviously pumping if it’s running but it may not be able to keep up with the engines demand for fuel...maybe a fuel filter on the frame rail, near the carb, or maybe even in the inlet line for the carb could be gummed up... In my expierence an Edelbrock can be kind of finicky as well. When they are right they’re right...but man when they’re wrong...ugh Me personally, I always did better with a Holley.

Fuel tank, pump, sending unit, and filters are all less than 3 weeks old. I’m thinking the carb but not sure where to begin. Getting a vacuum gauge to check the carb will be next. Tried spraying carb cleaner around the carb and no vacuum leaks show up either. Need to trace the fuel lines for any kinks.

 

[whiskerz]

Needs faster distributor advance, try to get total in at under 2,000. Why are you not using the vacuum advance? Can we assume stock cam ? turn the idle up a hair. Are the plugs right ? right firing order ? Do you have enough voltage ? 13.5-14 running ?

 

[joel2000]

I’d lean to float level and/ or power valve possibly

 

[barlowlc]

Might want to recheck the plug wire. It is posssible one got crossed with another when they were changed...Made that mistake myself...ooops

 

[grandall1972]

Have you had the top off of the carb?

Yes took the top off and it looks brand new inside. Floats are correct, jets are clean, and other pieces were removed from inside and checked for flow and cleanliness. Not sure what jets are in it currently though, I think it’s yellow springs, and other than that I’m a bit lost.

If I play with the choke cam on the drivers side while throttling up it’s a little smoother and revs better.