Carb idling problems on 65' C-10 with 292

[runningiron]

Need some help with my 1965 C-10. It has an original 292 with approx 158K miles, 3 speed on the tree. Recent tuneup, new plug wires, plugs, dist cap, points. condenser, new fuel pump and rebuilt 1 barrel Rochester with manual choke. Stock exhaust. I timed it 4 degrees btc, dwell at 31. It is hard to start and takes what seem to be a long time to warm up. The carb stumbles and pops back through the carb at times, not all the time. What am I missing here? Thanks for any info in advance.

[geezer#99]

Lack of timing and/or heat riser stuck.

[runningiron]

geezer#99, thanks for responding. Here is a photo of my heat riser and it is frozen in that position. It almost looks to me like it has backed out some. What would be a quick fix on that? Also how much timing would be better that the 4 degrees BTC? Thanks.

[geezer#99]

Looks like it’s stuck open.

Try timing at 12.
Be sure to plug off vac advance hose while setting timing.

[runningiron]

geezer#99, I'll be sure and plug off vacuum advance and try timing it at 12. Thanks.

[jayoldschool]

More timing makes it harder to start, not easier.

First thing I would do is triple check the plug wires, put it at TDC, and check the cap/rotor. This could be a firing order issue when I hear about the backfiring.

[runningiron]

jayoldschool, thanks for your input. I will check the position of the plug wires.

[vince1]

What kind of spark does it throw? It should be blue and jump a gap of about 1/4" or more.

The accelerator pump in the carb is working good?

[SkinnyG]

+1 on the plug wires first; it's an easy fix.

If it only pops through the carburetor when you're trying to accelerate, it sounds lean. Maybe lean mix, maybe a problem with the accelerator pump.

By "hard to start" do you mean slow jerky cranking, or you have to crank it for a long time?

And I have to ask - you're pulling the choke to get it running, correct? And slowly pushing it in as it warms up?

[runningiron]

I want to thank all that responded. Turned out to be part vacuum leak and timing. Thanks all.