Model A Troubles

[drpepper1885]

Dear fellow Model A’ers:

Hello everyone. I took the Model A out for a spin and she did fairly well for a while. I just got her back after having the engine rebuilt. Unfortunately, I am running into some puzzling issues.

She idles very high and if the throttle gets below half-way on the quadrant (between the top of the quadrant and half-way down) she immediately dies. As we were driving her and turned a corner in one of the neighborhoods, she died. We were going about 15-20 mph as we approached the corner and I applied the clutch then brake since we were in 3rd gear. I was downshifting and she just quit. When I tried to restart, the starter would turn over only one time and nothing else. After about twenty minutes, she finally restarted and we nursed her home.

When I got home I put on a brand new Zenith carburetor, replaced the throttle rod going to the carburetor, the gas line from the sediment bowl to the carburetor, and installed a new choke rod. I encountered the exact same problem with new carburetor. She has to have a lot of throttle to start up, now more than half-way down the quadrant. If I decrease the throttle advance below half-way on the quadrant (as described above), she immediately dies. Also, I noticed a little bit of backfiring with the new carburetor. Intermittently, I am getting the one turnover on the starter and then nothing.

I tested the battery by applying the starter with the lights on. The lights dimmed considerably. I have a brand new alternator on the car.

So, I am left with the following questions:

1. I am having the same idling issue with both carburetors (one a rebuilt original and the other a brand new manufacture). I did not adjust the carburetor I purchased from Brattons since it was supposed to be pre-set. It can’t be right to have to run the car at a racing idle.
2. Is it my battery? I am going to check the voltage right after I post this.
3. Could the new alternator causing any of these issues? Seems like it wouldn't, but everything is on the table.
4. Is this a timing problem? Has something perhaps gone out of adjustment on the rebuilt motor?

Your thoughts on these questions are most appreciated.
Thanks so much for your help.

[drpepper1885]

Checked the battery...a strong 6 volts. Rule that out.

[Tom Wesenberg]

Originally Posted by drpepper1885

Checked the battery...a strong 6 volts. Rule that out.

Did you have a load on the battery when you checked the voltage? What does it measure while cranking the engine? What does it measure with the lights on? A good 6 volt battery should measure about 6.4 to 6.7 volts with no load, and should still show about 5 volts while cranking the engine with a stock head.

A hydrometer check is also a good way to test a battery.

[Barry B./ Ma.]

You could have a vacuum leak. Check the manifold for cracks and leaks at the block surface. Does it pick up speed if the choke is pulled out part way?

[1931 flamingo]

DITTO on the vacuum leak.
Paul in CT

[eagle]

Sponsored Links (Register now to hide all advertisements)

When its running, spray some ether or wd40 around the intake manifold CAREFULLY, use a can with a "straw" on it. The engine will speed up if there is a leak. That won't be causing the starter issue though... When the starter won't turn over the engine, use the hand crank and see if the engine turns over hard.

[Aerocraft]

Check the fit of the gaskets between the manifold assembly and the block. You may find that the intake is not sealed correctly to the block. Easy fix........ Gar Williams