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10-05-2023, 07:37 AM | #1 |
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Join Date: Jan 2022
Location: Rochelle Park, New Jersey
Posts: 86
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Model A Lagging and Popping when Accelerating
Hi everyone,
The past few times I've driven my Model A, I noticed it loses a little power and pops a bit when accelerating. It idles ok. I'm wondering if there might be a couple of reasons why it might be doing it. I'll give you the scenario from starting to driving in the morning. I retard the spark lever all the way up, pull the throttle lever about 1/3 to 1/2 down, open the GAV to about 1/2 to 3/4 open, open the gas valve, pop out the ignition, pull the choke and start the car. It usually starts right up on either the 2nd or 3rd crank. I then pull the spark lever down about 1/2, push the throttle lever up to idle and turn the GAV to about 1/4 open. I let it idle for a few minutes while I move my other cars out of the driveway and get my stuff together for work. I then back it out, and start driving. As I accelerate out onto the main road is when I notice it lag a bit and pop a couple of times when accelerating. Most of the time, after a little while of driving, it starts picking up the pace and stops popping. Could it be any of the following?
Thanks as always in advance. John |
10-05-2023, 07:52 AM | #2 |
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Location: Long Island, NY
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Re: Model A Lagging and Popping when Accelerating
Hi John! Does your engine behave the same when it is thoroughly warmed-up?
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10-05-2023, 09:08 AM | #3 |
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Join Date: Jan 2022
Location: Rochelle Park, New Jersey
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Re: Model A Lagging and Popping when Accelerating
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10-05-2023, 09:33 AM | #4 |
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Location: Red Deer, Alberta
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Re: Model A Lagging and Popping when Accelerating
Sound like it needs a good cleaning of the carbutetor.
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10-05-2023, 10:02 AM | #5 |
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Re: Model A Lagging and Popping when Accelerating
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10-05-2023, 10:13 AM | #6 |
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Re: Model A Lagging and Popping when Accelerating
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Doug in Waterloo |
10-05-2023, 10:14 AM | #7 |
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Location: Western North Carolina
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Re: Model A Lagging and Popping when Accelerating
Too lean. Open the GAV more for the first few miles.
You can put a can of injector cleaner in your tank. It will clean out the gum in your fuel system, including the carburetor. Buy that at your local auto parts store. It does not have to be specifically for carburetors, any injector cleaner will work, like Gumout. Play with the ignition lever. Try advancing it more. Advance to the point where further advancing will not increase rpm or power then retard one notch. Use different ignition advance under different conditions. Retarded one notch in town or under heavy load at low rpm, advanced one notch when driving on a level road at a constant speed.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
10-05-2023, 10:24 AM | #8 |
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Join Date: Jan 2022
Location: Rochelle Park, New Jersey
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Re: Model A Lagging and Popping when Accelerating
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10-05-2023, 10:29 AM | #9 | |
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Join Date: Jan 2022
Location: Rochelle Park, New Jersey
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Re: Model A Lagging and Popping when Accelerating
Quote:
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10-05-2023, 11:01 AM | #10 |
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Join Date: May 2023
Posts: 172
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Re: Model A Lagging and Popping when Accelerating
What works for me on cold starts is:
Ignition advance fully retarded Throttle lever pulled down 2 or 3 notches GAV valve 1/2 turn further than it's normal position Then pull the choke and hit the starter simultaneously. It fires up and I release the choke. Then pull timing down about halfway but leave the GAV/throttle lever alone. I Then adjust the GAV until the engine runs as smooth as possible and let it "fast idle" like that for a minute or so. Usually that means I'm adding a little more fuel via the GAV to smooth it out Then after a minute or so after that drop the idle back down and take off. I've got a temp gauge, so once engine temp hits about 130*f, I back the GAV down to its normal position No pops or problems with that method. Engine runs nice and smooth from cold start |
10-05-2023, 12:51 PM | #11 |
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Location: Western North Carolina
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Re: Model A Lagging and Popping when Accelerating
Follow the instructions on the bottle. Some additives say to add more initially and then less after that.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
10-05-2023, 01:18 PM | #12 |
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Join Date: Jan 2022
Location: Rochelle Park, New Jersey
Posts: 86
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Re: Model A Lagging and Popping when Accelerating
Thanks for all the great advice everybody! I'm going to keep the GAV open more and the spark rod little further down when I drive it home from work and see how it runs. Even if I don't get any popping, I'm going to put the gumout in and double-check the distributor shaft and points when I get home.
I'll update you all after I perform all the checks. |
10-05-2023, 05:18 PM | #13 |
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Join Date: Jan 2022
Location: Rochelle Park, New Jersey
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Re: Model A Lagging and Popping when Accelerating
Ok, update time.
I checked out the instructions on https://modelabasics.com/Ignition.htm that gave instruction on the ignition system. First I checked the gap from the rotor to the contacts on the distributor cap. One or two gaps were a little too wide, about .030, so I adjusted the gaps. I then removed the rotor and distributor cap and checked the shaft, which was fine. I then checked the point gap and that was pretty much at .020. The site also mentioned that the spark arm on the distributor shouldn't be hitting the distributor body at all, and it was, so per the instructions, I loosened the steering column clamps and slightly rotated the column until the arm wasn't hitting the distributor anymore (a much bigger difference than before). Lastly, and this was the weirdest thing. I decided to replace the fuel line because the nuts on the old one are a little stripped from when we were first getting back together about a year ago. The funny thing was, when I started the car with the new fuel line, it ran and then stalled, and wouldn't start again, like I didn't open the gas valve or something. I was contemplating putting everything right back where it was, but then thought what if I put the old fuel line back on? I took the new fuel line off (it DID have gas in it), put the old one back on, and it started and ran, so I don't know what the problem with that was. I took the car for a drive and it didn't lag or pop, so maybe I did something right. |
10-05-2023, 06:02 PM | #14 |
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Join Date: May 2023
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Re: Model A Lagging and Popping when Accelerating
I'd check to see how hard it is to blow through your new fuel line. It may be partially obstructed
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10-05-2023, 06:15 PM | #15 |
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Join Date: Jan 2012
Location: Western North Carolina
Posts: 4,052
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Re: Model A Lagging and Popping when Accelerating
If the end of the fuel line is too far into the carburetor it will stop the fuel from flowing.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
10-06-2023, 07:45 AM | #16 |
Member
Join Date: Jan 2022
Location: Rochelle Park, New Jersey
Posts: 86
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Re: Model A Lagging and Popping when Accelerating
Do any of you think I should look at the timing or anything after doing that work on the points and rotating the steering column to line up the distributor arm correctly? It seems to be running ok, but it did feel like a little bit of a rough idle last night and stalled (maybe it was the GAV again).
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10-06-2023, 08:04 AM | #17 |
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Location: Largo Florida
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Re: Model A Lagging and Popping when Accelerating
Open the GAV and give it a good dose of Sea-Foam.
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10-06-2023, 08:24 AM | #18 | |
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Location: Red Deer, Alberta
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Re: Model A Lagging and Popping when Accelerating
Quote:
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10-06-2023, 09:01 AM | #19 |
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Re: Model A Lagging and Popping when Accelerating
A past member Tom Wesenberg always said “ set the timing and forget it “ unless you mess around with the distributor cam. The points follower can wear and change the timing, resetting the points will bring the timing back. Have you adjusted the idle speed and idle mixture yet? Only adjust the carburetor after your engine is fully warmed.
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10-06-2023, 10:15 AM | #20 |
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Location: Western North Carolina
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Re: Model A Lagging and Popping when Accelerating
Do you have someone nearby that can help you. Easiest way to learn sometimes is watch someone who has experience.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
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