starts but won't run

[wingski]

OK, I need help. I have done everything I can think of get my A running. However, it starts immediately but won’t keep running without missing and back-firing. I’ll list the things I’ve done and maybe you can tell me where I went wrong.

1-New fresh gas is in the tank. Filled tank to 1/2 full.
2-Installed new headgasket, used Indian Chief shellac, and torqued to 55 ft. Lbs in three stages and then torqued in reverse order.
3-Ran compression check- #1 56 psi #2 53 psi #3 55 psi and #4 60 psi.
4-Removed timing gear cover and the notch in the crank gear lined up with the dimple in the cam gear.
5-Made sure the cam plunger and spring were good. They were new.
6-Drilled out dimple enough so timing pin fits securely when in hole and bolted cover back on.
7-Set distributor so rotor was pointed at #1, set the point to .020 and spark plugs to .035, and backed up the distributor cam so the points just closed while the timing hole in the cam gear was lined up with the timing pin.
8- Turned timing pin around and turned crank back from timing mark and turned crank forward. Points sparked when rotor was pointed at #1.
9-Made sure gas was getting to the carb
10-Checked plug wires for continuity. They are good.
11-Tightened all intake, exhaust, and carb mounts. No air leaks.
12-Made sure gas cap was venting correctly. It is.
13-Turned key on, retarded spark, pulled throttle lever down two clicks, opened rich/lean knob 1/2 turn, pulled out choke, and pushed starter.
14-Engine started immediately, but never smoothed out when I pushed the choke in. I pulled the choke back when the engine tried to stall, but all it did was back-fire and finally stalled when I pushed the choke in.
15- I tried starting it three different times allowing 15-20 minutes between attempts. The results were the same or close to the same each time.

I don’t mind asking for advice, but I really hate to ask for help because I’m soo stuborn. However, I’m at wits end with this thing.

Mike

[Craggles]

Maybe a manifold air leak or sticky valves. I believe the auto trans fluid or mmo in the oil can relieve sticky valves, a oil flush did the trick for mine.

[SuperDave]

try opening the GAV another turn. Sounds like it's too lean.

[Glen in Hillman MI]

Check strainer in carburetor ? Check gas flow with strainer out, gas line could be in too far.
Glen

[Jacksonlll]

Try a different condenser. You have a higher probability of a new one being bad than a good one going bad. Make sure of the timing. The coil fires when the points open. Use a light and go by the book.

[Tom Wesenberg]

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Originally Posted by SuperDave

try opening the GAV another turn. Sounds like it's too lean.

X2
Mine needs to be open 1 1/2 turns for a couple minutes.
As soon as the engine starts, pull the spark lever half way down.

[Sunnybrook Farm]

Was it running and then acted up or are you trying to get it started for the first time?

[barkleydave]

No mention of Carburetor in your check list? Assuming timing is correct or close... they will run even if off 10 degrees retarded. When was the carb gone through? Keep digging you will find the it.

[Big hammer]

Mike mentioned fuel to the carb, he didn't say fuel in the carb :-(

[katy]

Pull the throttle lever down a bit more.

[700rpm]

I suspect a fuel problem. Make certain neither end of your fuel line is pushed too far in, which would restrict gas flow. Also make sure your sediment bowl is not full or clogged.

[abachman3]

When it runs better with the choke pulled out (Closed) this suggests a lack of fuel. As mentioned above, try starting with the GAV opened more, at least a full turn or slightlt more.

[wingski]

Originally Posted by Craggles

Maybe a manifold air leak or sticky valves. I believe the auto trans fluid or mmo in the oil can relieve sticky valves, a oil flush did the trick for mine.

I have a MMO jar with the oil in it mounted on the firewall, but I don't know how to use it. I don't want to use that Marvel stuff until I figure out how much to open the valve on the dispenser. I would think that my compression values would show that the valves are working correctly, but who knows?

[wingski]

Originally Posted by 700rpm

I suspect a fuel problem. Make certain neither end of your fuel line is pushed too far in, which would restrict gas flow. Also make sure your sediment bowl is not full or clogged.

Ray, I’ve been told by several different members that the fuel line ( in my case, fuel lines) could be pushed in too far, but I don’t see how. I’ve attached a photo of the front carb because I’ve got the back carb diconnected from the fuel line with the choke wired all the way closed. I’m hoping that if it is a carb problem I can get it running on the one and work from there.

I appreciate your advice and wish I didn’t live so far away from someone who really knows A’s.

Thanks again,
Mike

[1crosscut]

Answering the question in post #7 could possibly help with diagnosis.

[George Miller]

Originally Posted by wingski

Ray, I’ve been told by several different members that the fuel line ( in my case, fuel lines) could be pushed in too far, but I don’t see how. I’ve attached a photo of the front carb because I’ve got the back carb diconnected from the fuel line with the choke wired all the way closed. I’m hoping that if it is a carb problem I can get it running on the one and work from there.

I appreciate your advice and wish I didn’t live so far away from someone who really knows A’s.

Thanks again,
Mike

are you saying you have two carbs? If so it is another ball game.

[40 Deluxe]

I haven't read all of your posts on this matter, but one thing caught my eye on your timing. You mentioned turning the points cam to where the points just closed. It should be to where the points just start to open with the rotor pointing to #1. This is just an initial setting. Actual timing is set by the spark lever on the steering column.
Is this a rebuild that has not run yet, or are you reviving an engine that has sat for awhile? If it was running before, leave the timing alone. That does not change from just sitting.
If you're trying to get it running on just one carb, remove the other one and make a block-off plate to cover the intake port. Just make a gasket or shim without the center opening and put the carb back on. Otherwise the engine can suck air around the throttle shaft and plate, through the float bowl, etc. and make the back cylinders lean.
Your carb fitting does not appear to have a line going into the carb so no problem there.

[wingski]

The car came with the dual Tillotsons, and the previous owner never got it running for more than a minute or so. I have the original Zenith and manifold and both are in good shape, but I’d like to get this thing running with the Tillotsons to see if they actually add 10 hp. If you really feel that this is a carb problem, I can put the old Zenith back on. Those Tillotsons look really good, but are worthless if they won’t give me a smooth running engine.

Mike

[Bill G]

Originally Posted by wingski

The car came with the dual Tillotsons, and the previous owner never got it running for more than a minute or so. I have the original Zenith and manifold and both are in good shape, but I’d like to get this thing running with the Tillotsons to see if they actually add 10 hp. If you really feel that this is a carb problem, I can put the old Zenith back on. Those Tillotsons look really good, but are worthless if they won’t give me a smooth running engine.

Mike

Maybe that would be a good starting point just to see if the problem can be isolated to the fuel/carburetor system.

[Bill G]

Besides, if you don't have the original to compare the dual carb to, how will you actually know the difference?

[1955cj5]

Originally Posted by wingski

The car came with the dual Tillotsons, and the previous owner never got it running for more than a minute or so. I have the original Zenith and manifold and both are in good shape, but I’d like to get this thing running with the Tillotsons to see if they actually add 10 hp. If you really feel that this is a carb problem, I can put the old Zenith back on. Those Tillotsons look really good, but are worthless if they won’t give me a smooth running engine.

Mike

You will have to get both carbs working together if you want it to run.

Blocking one carb off does not mean it will run on the other.

Even though the manifold may have a cross-over tube that is more for balance than to allow it to run on one carb.

I have a dual carb MGA and if one carb drops off for whatever reason it will just barely run on the other if at all. It too has a cross-over tube between the carbs.

[Craggles]

The condenser is a good point, they can do strange things. Have you checked you are getting a bright blue spark from your coil, I would check all four plugs. I assume once it is starting you are moving the spark rod hitting the accelerator and what effect does that have - it could be too far retarded. By pulling the choke this makes the motor pull fuel into the motor and why I suggested an air leak but it also helps the motor pull it down from the tank which would indicate a restriction or float issue. Dual carbs do change the problem, have you gone through the process with tuning these idle and idle mixtures. Are you sure your cam was set correctly, maybe do a compression test and see how it lines up with the distributor.

[mantta]

You said turned to #1 points just closed. You want it so the points are just opening with the spark fully retarded.

[1crosscut]

Originally Posted by Magicbox51

Maybe that would be a good starting point just to see if the problem can be isolated to the fuel/carburetor system.

I agree. Put it back to stock with the original carburetor and manifold and get it running well that way. Then you can tinker with a different set up. Too many variables this way trying to get a car to run for the "first" time.

[JBill]

That doesn't look like any Tillotson I've ever seen, but they might have made carbs for the Model A other than the Model X.

[William Kelchner]

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I've had numerous problems with my machine, would run for a few minutes, then it would not run at all. Me, I found out I know nothing about the car despite tinkering with it for 10 years - it runs ok now and I swear it is because I took the advice given to me here on the forum by more than one - "most carb problems are electrical!"

I replaced the distributor!

[700rpm]

You left out very important info in your initial post. It is hard to give relevant advice when we don't have all the facts and don't know what your setup is. As George says, two carbs changes everything, and two Tillies complicates the problem even further. But I'll take some blame for assuming we were dealing with a stock system. Messing with Henry's engineering always runs the risk of problems, especially before you are familiar with how the car runs stock. Take the dual carbs off and install your stock manifolds and Zenith.

[George Miller]

Two carbs can be a big problem dialing them in. It is not as easy as bolting on two carbs. The manifold makes a difference, carbs also. It is not that easy to get them to work right on a stock engine. My advice is go back to stock, get it running right, then try out your dual set up. You might be better off with a B carb and a bored out intake.

[abachman3]

The picture looks like a Marvel Schrebler... not a Tillotson... (for what it's worth).

[wingski]

Originally Posted by abachman3

The picture looks like a Marvel Schrebler... not a Tillotson... (for what it's worth).

Thanks, I'll look up the Marvel carb. I've been told that Marvel carbs were pretty good carbs, and if I can find info about them maybe I can get these things to work eventually.

[abachman3]

Several of my fellow club members and I all use Marvel carbs. Renners Corners makes parts and will rebuild the carbs for you.