Ran fine for 1 month, then mucho problemas

[Rascal]

Got my '76 Spider running after 14 yrs. in the garage, ran great for a month. Cleaned out the old gas. Perfect idle, great performance. Engine sounded smooth and quiet. Fell back in love with the little Spider. Life was beautiful.

Started it up the other day, the fuel pump made some disturbing noises, but quieted down. Felt like poor power at low rpm's. It seemed to hesitate a little when pressing the throttle down, then picked up power as rpm's increased.
Came to a stop and the engine stalled. The engine wouldn't start and after a few tries, the battery was to weak to turn it over. Got a jump, but now the charging light was on (maybe I missed it at first). It wouldn't stay running unless I kept the rpm's up, but I limped the 1 mi. home. Next day, I got the battery all charged up, it turned over fast, but it barely started, and wouldn't keep running without using almost full throttle. It sounded like it's not running on all cylinders. The charging light is still on. Now it backfires out the carburetor and won't start. Seeing it spit a flame out the carb was just too scary.

What should I check first?

[So Cal Mark]

this is pretty typical of cars that have sat for long periods. Anything with rubber in it fails shortly after getting them running.
Your first step is to get full voltage from the battery and get the charging system working.
Popping back through the carb is usually from a lean condition. It could just be a failed accelerator pump diaphragm, or dirt in the carb

[Rascal]

Since it's hard to diagnose charging probs when the engine isn't running, I guess I'll remove and clean out the carb and look for broken hoses. It looks like the PNW weather won't be nice again until next July 5th, so the carb will be a good indoor project.

[rasouth]

The battery is primarily used for starting the car, after that the alternator takes over. Your problem may be caused by the alternator or voltage regulator not producing enough power to send a good spark unless the rpm's are high. Another thing to check is the ground wires.

[Exit98]

The battery is primarily used for starting the car, after that the alternator takes over. Your problem may be caused by the alternator or voltage regulator not producing enough power to send a good spark unless the rpm's are high. Another thing to check is the ground wires.

I agree with Rasouth. Don't fool around with the carb yet. Get the charging system squared away.

George (NJFIAT1981) just mentioned to me last night that (I think he said) AutoZone will test your alternator for free to see if its working. My guess is you need it repaired, or maybe the regulator.

Good luck.

[majicwrench]

Always fun to see differences of opinion. I agree with Rascal, it has to run BEFORE you can fix the charge issue. With a well charged battery it will run fine for hours before voltage gets low enough to cause ignition issues.
When you say fuel pump noisy, is it electirc or mechanical??
Keith

[Rascal]

My cursory inspection today revealed the distributor clamp was loose! The points look a little rough, but the distributor cap looks fine. We''ll see what new points/condenser and setting the static timing will do.

The fuel pump is electrical. It sometimes makes a kind of screeching sound, then changes to a soft whirr. It doesn't sound happy, although I checked the fuel filters on it and they look ok. The carb looks wet with gas, maybe too much?

[rasouth]

I would not let Autozone (or anybody else) check the alternator whilst it was in the car. I had them do that and they told me it was okay only to find out that their equipment was checking the voltage in the battery and not what was coming out of the alternator. My alternator needed a new voltage regulator