1976/1977 Dump truck holley carb adventure

[Cariboo4x4]

Hi All. This singke axle chevy dump truck with HEI ignition and holley carb wont rev past 2500 rpm, won t idle, and stalls if we don t keep foot on pedal a bit. Choke is manual and helps to keep engine running yet it still stalls on or off. Its like its running on 4 cylinders and no power. So I took off cap and rotor. Definitely worn. I put a better cap and rotor on and still ran the same. It ran good couple weeks ago when we just started it up after sitting for 10 months and then went to move it into the shop and it stalled 6 times or so. Then Monday it seemed to run bit better. Then yesterday it ran like I described. So I figure carb may be faulty. I removed carb and rear float bowl and the one big gasket shrunk to the point that will not go back togther properly. There was a c clip lying in float area and there was c clip holding float on so don t know where the extra c clip came from. I figured might as well disassemble carb snd order a carb kit. I removed front float bowl and the accelerator pump I think is faulty yet not sure. Its not like a quadrejet accelerator pump. The holley accelerator pump, it seems to move a lot less Fuel compared to a q-jet. This is my one of very few holleys Ive worked on. I m pretty sure the engine running symptoms point to the carb. The gasket that shrunk appears to have shrunk before I removed rear float bowl because it is split at one of the bolt holes. Maybe the gasket was blocking off ports. Any feedback I d appreciate.

Here is the id info and couple photos
793981
LIST-7386
1346

 

[Cariboo4x4]

Man oh man its proving harf to find a carb kit. I found a number looking down on carb 6R 4461 B Its like the 4461 is in bold. The Holley website is not helping yet I m still looking

 

[Cariboo4x4]

So the carb list number 7386 stamped on vertical front of air horn is the number I needed or R7386. Local parts store has "Bluestreak 1602" kit coming in for me. Looks like the right kit. Hopefully a carb kit will solve the engine running problems. Please chime in if you agree or think otherwise or other items to check. Thank you

 

[Nordic]

Have you ruled out restricted fuel supply to the carb, like a plugged filter somewhere or even a tired fuel pump?

 

[Cariboo4x4]

(quoted from post at 14:05:45 09/23/23) Have you ruled out restricted fuel supply to the carb, like a plugged filter somewhere or even a tired fuel pump?

Yes the clear plastic in line fuel filter was right full entire time as it was running and both float bowls right full when I opened the slotted screw on top of each float bowl.

 

[Tom in Mo.]

It's too late now but the first thing I woulda done is give it a heavy dose of Seafoam. I'm not a fan of snakoil stuff but Seafoam has saved a lot of grief and revived several engines for me over the years.

 

[Cariboo4x4]

(quoted from post at 04:36:37 09/25/23) It's too late now but the first thing I woulda done is give it a heavy dose of Seafoam. I'm not a fan of snakoil stuff but Seafoam has saved a lot of grief and revived several engines for me over the years.

Yes Seafoam I ve been learning is great stuff!

 

[Mad Farmer]

(quoted from post at 11:24:14 09/23/23) Hi All. This singke axle chevy dump truck with HEI ignition and holley carb wont rev past 2500 rpm, won t idle, and stalls if we don t keep foot on pedal a bit.

Sitting 10 months.

Did it have E10 in it? Sure it's not bad fuel?

 

[Cariboo4x4]

(quoted from post at 19:19:28 11/03/23)

(quoted from post at 11:24:14 09/23/23) Hi All. This singke axle chevy dump truck with HEI ignition and holley carb wont rev past 2500 rpm, won t idle, and stalls if we don t keep foot on pedal a bit.

Sitting 10 months.

Did it have E10 in it? Sure it's not bad fuel?

I m glad you replied. Not sure what E10 means.

It turned out to be bad HEI ignition coil. As soon as I replaced ignition coil in ran good again and revved up way past 2500 rpm

 

[Tom in Mo.]

E10 refers to the menthonol they put in gas now.
Coils don't go bad very often but they will do just what you described. The bad coils I've had show fault when they get hot.
Hope you got that Holley back together.

 

[Cariboo4x4]

(quoted from post at 03:29:35 11/05/23) E10 refers to the menthonol they put in gas now.
Coils don't go bad very often but they will do just what you described. The bad coils I've had show fault when they get hot.
Hope you got that Holley back together.

Thank you. Yes got holley back together. Its running well.