Re: Starting a 1929 Packard 8 with straight 8 and Detroit Lubricator Carb.

Posted by Fish'n Jim On 2023/11/21 10:49:58

Most likely it's the carb since you're not getting fuel mix and the pump is delivering, if not too much. Without a pressure regulator, it's probably delivering too much pressure and overcoming the needle valve going out the overflow. I'd have to look in my motors manual, the Packard section I sent to Kevin to post years ago, so that should be on here.
These are notorious carbs, hand built, and require expert restoration, so better to not fiddle with it yourself. There's a guy making "new" repro ones, but at two arms and a leg X 10 price which is probably about right. Refer AACA posts on these carbs.
Two components here, the age of the item and the technology of the day. So it's not going to compete with a 2023 w/ FI/HEI. Since it's worse with down period, it's drying out and not re-flowing.
That's can be fuel tank/line issues or deposits. Some of these early ones had gravity or vacuum flow. Maybe why the electric is on it. Rather than fix them, many just by-passed the fuel delivery issues. They were meant for momentary use to get things rolling. I don't recommend that DIY approach. Just as complex tech troubleshooting can confound, simple can be a hair puller, as well, as it's not apparent why it won't work being so freaking simple. Fundamentals persist. Procedure over hunt and pecking.
As noted, the condition of the motor is also in play. But it's should start if it's getting the correct fuel/air ratio and spark. As it apparently does once things get "over the hump". Low compression is easier to fire than high, but a weak spark should be corrected.
I ran a >100k mi. SBC on 7 cylinders for years after the second cam wiped. So that part doesn't need to be perfect and if no noises or hard turning, it's bottom end must be sound. It becomes an issue at some 'EOL' point and usually economics of constant repair to keep it moving vs bite the bullet. They won't last forever without regular wear part maintenance. Intermittent use will always bring start-up issues.