All Small Six New guy with Comet dying leaving a stop

This relates to all small sixes
What else do you think could be causing it? The engine is stumbling at idle too, like it’s missing a beat. The cap contacts are clean, rotor and points look new, plugs are good, wires are good and timing is rock steady at 12 btdc.
Re idle stumbling
Have you checked with a vacuum guage .
can troubleshoot a lot of problems ieburnt,sticky leaking valves etc

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Good news boys! I swapped the carb with the new one they sent me and took my daughter to the store and driving around. She ran great and didn’t die or stumble once. It’s probably premature to call it fixed because it’s a cool night, but it ran awesome. That makes me feel better. I did buy a fuel gauge and vacuum tester, they will be here tomorrow.
 
Re idle stumbling
Have you checked with a vacuum guage .
can troubleshoot a lot of problems ieburnt,sticky leaking valves etc

View attachment 23739
Just for my own knowledge I put a vacuum gauge on it, as well as a fuel pressure gauge. The vacuum gauge holds steady at 21 and drops below 5 when I snap the throttle full open to closed. No fluctuation to speak of at idle and moves as would be expected for smooth throttle changes.


The fuel pressure is at about 7, jittery, but doesn't drop from that. I'm assuming that jitter is from it being a cam driven mechanical pump. Am I wrong in that assumption?

Not sure if the video will attach to this post, but here is a link to it:


And the fuel pressure:

 

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That's the upper limit of fuel pressure, really should be less. A common situation with mechanical pumps.
Vacuum is good/normal.
 
That looks to be a fair amount of bounce in your fuel pressure reading, for having a liquid-filled gauge. It may be how you have the gauge mounted also. Any air passing by will cause that. I have mine mounted closer to the pump at about a 45 degree angle and carries a nice smooth 6.5 psi reading.
Reason for mounting the gauge in a more vertical position is because it is a sealed air-tight component; there is a rubber cap on the top of the gauge that you want to occasionally lift up to equalize the sealed pressure to atmosphere. This is usually done whenever there is a seasonal temperature change. Just be careful not to lose the cap!!
 
Had a really good experience with carbs.us Just provide them the model number and they will send you photos of what they have.
 
A fuel filter should be the screwed into the carb. That way it is at the best place to keep debris out. The way it is now just connecting the fuel line to the carb can peel off some pieces of the rubber hose that will wreak havoc with the small fuel passages in the carb.
 
Just a follow up - I think I have the issue resolved. My theory is that the heat issue was from the mechanical pump being physically attached to the block and transferring head into the fuel that was sitting in the filter. I insulated the fuel line from the pump up and still had the issue, that's what leads me to believe that. In the end I bypassed the mechanical pump and used a Carter universal pump mounted at the tank. I took it on a drive yesterday, probably 30 miles, and it had no hiccups at all. Now, it's cooler outside, so that may play a part, but I feel fairly confident that I have the issue resolved. I will order a second Carter pump to leave in the trunk, as I have trust issues with electronic fuel pumps, but for now I'll call this one solved.
 
I thought you said the carb swap fixed it? Or did it start to run badly later on with the carb swap after all?

Honestly there’s not that much heat to be transferred at the mechanical pump with it being crankcase temperature and on the other side of the block from the exhaust. I can keep my hand around my mechanical pump when running because it’s not that hot. When you say a pump at the tank fixed the issue I don’t think heat, I think restriction in the line. Fuel pumps are much better at pushing pressurized fuel through a line restriction than trying to “pull” unpressurized fuel through a restriction (this might even make a mechanical pump run hotter, working harder with less fuel flow, and causing vapor locks). I think you might have just moved the pump to the other side of the restriction and solved it (at least until the restriction gets worse and burns out the pusher pump- been there done that with a clogged inline filter).
 
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Thanks Scott. I thought the new carb fixed it until I drove a little while and it died again. It does seem to be resolved now, so I hope this fix, even if it's just moved to the other side of the problem, works for a while.
 
I will order a second Carter pump to leave in the trunk,
I like your thinking. However, with the infrequency of opening and the day to night hot/cold, trunks tend to become inherently humid. I would spray a fair amount of wd-40 inside the pump and make sure the inlet/outlets are tightly capped.

How does the fuel pressure read now on the gauge?
 
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