I have a '26 Roadster with a holly NH center drain carburetor that ran great up until 2 months ago. Now it won't start and I've narrowed it down to the carburetor. When I try to start it it will sometimes catch and spit and sputter very erratically and it has backfired a couple of times. The manifold gets very cold when this happens. So I think it's a mixture issue. The needle was pitted like it had been screwed down too hard. I took my chances and ground the needle (very carefully) until it was smooth again. I replaced the bowl gasket and checked the float. All seems okay. Any ideas?
"The manifold gets very cold when this happens." that's normal without a heat stove or the intake gets warmed up. If you have good flow when you open the bowl drain, try opening the spray needle more. Sounds like it is not open far enough. Each car is different so suggesting to open X amount depends on your car. Better to start a little rich then too lean.
Also check and make sure the timer is clean or points are gaped correctly.
Try to start by spraying a little starting fluid into the mouth of the carburetor while cranking the engine. If it starts right up but sputters to a stop, it would be a good indicator that the carburetor is running too lean or not letting any fuel into the intake. If it continues to run after starting with the starter fluid, it would indicate the carb might need to be set a bit richer and the choke used to get it to start. If it still won't start with starter fluid, it would indicate either very low compression or an ignition problem.
If you've (accidentally) altered the taper on the needle you've changed the settings. Experiment.
I am in Georgetown. Bring your carburetor over and I will fix it.
Nothing like getting help from an experienced T guy. Take Royce up on his offer.
But, in the mean time if it was me.... I assume you made sure you had proper full flow and it wasn't blocked. I would then be inclined to drop the bowl to make sure you don't have crud/corrosion buildup from todays wonderful gas. I would also check the inlet and spray needles for build up too. Pretty simple carbs to work with.
I will take you up on that, but I'm out of town until the 15th. Would you be available on the 16th?
I took the commutator off and it was really dirty. I was hopeful that would fix it, but I'm not getting any catch at all. I'm not convinced it's the carb anymore, but if Royce looks at that, it'll either solve it or eliminate it. I did take the bowl off and cleaned out, it wasn't bad.
Remember the old sage advice...
90% of carbureator problems are electrical.
I would still take the carb and make sure it's clean and in proper adjustment but make sure you have spark and plugs are clean, timer etc.
I am in California this week, Montreal the week of the 17th, and in New York City the week after that. I am going to be home on weekends.
I will send you a PM with my phone number.
Skip, Just for grins and giggles you might want to check the tightness of the manifold bolts to make sure the intake gaskets or glands haven't started leaking. I had a similar problem that drove me nuts. My '26 Touring was tough to start (if it did at all), coughed, popped out the exhaust, and when it did run was incredibly rough for a pretty new engine. After going through the ignition, rebuilding the carb, changing spark plugs, I finally for some reason started to check the torque on the head bolts (all OK), and the manifolds. Front three were fine, last one had come loose and the seal on the intake gland was lost. Ordering new glands/rings today. A lean running cylinder would explain the problems.
Instead of using the old ether starting fluid I always use WD-40 instead. I have seen cases where people used to much starter fluid and the fumes will build up to the point that they can and will explode. I had a guy with a starting problem on a boat he told me I just used a tad of starter fluid. I finally found the problem in a broken hot wire going to the distributer fixed that and hit the starter. I thought the whole boat had blown up. What a blast. I think the tad of fluid must have been a whole can.