Engine sputtering - where to go from here?

[philcobill]

I just replaced the timing gear on my Special Coupe and managed to get it started. It idles so smoothly I cannot believe the difference. However, the engine sputters when I drive it, low speed or high speed, no difference. It has a tendency to want to stall.

I also adjusted the timing, and before the timing gear went out, I had carburetor issues.

Since changing the timing gear (which it has been established is installed correctly) I have been working hard to get the ignition system working. I have good spark, I have adjusted the points and the other things called for in Les Andrews' manual. So, I believe that the ignition system is good, although it might need some tweaking.

I have three carburetors at my disposal and swapped them out after working on the ignition system. They all have problems with sputtering and stalling, and hard starting but do not behave exactly the same way. Two of them were subjected to gas tank grit and were cleaned out.

My question is where do I go from here. I will field questions if it helps to fill in any gaps.


Bill
Walworth, NY

[fordwife]

gas cap vent? vacuum leak in manifold or ww wiper motor? Just some ideas.

[philcobill]

Originally Posted by fordwife

⛽ cap vent? vacuum leak in manifold or ww wiper motor? Just some ideas.

the gas cap is fine. New manifolds and gaskets, the old ones were warped. I have a vacuum gauge so it might be worth the time checking it out.


Bill

[BRENT in 10-uh-C]

Originally Posted by philcobill

the gas cap is fine. New manifolds and gaskets, the old ones were warped. I have a vacuum gauge so it might be worth the time checking it out.


Bill

Bill, are you a member of the Lakeshore Model-A club in Rochester? Surely there is someone in that club that can mentor you.

Without being able to physically hear and see things on the engine, we are all just throwing darts as what it could be. I think your time would be much better served getting someone local to you that has Model-A experience to have a look at it first before you start changing a bunch of things.

[philcobill]

Originally Posted by BRENT in 10-uh-C

Bill, are you a member of the Lakeshore Model-A club in Rochester? Surely there is someone in that club that can mentor you.

Without being able to physically hear and see things on the engine, we are all just throwing darts as what it could be. I think your time would be much better served getting someone local to you that has Model-A experience to have a look at it first before you start changing a bunch of things.

yes I am a member of the Lakeshore Model A chapter and am working with the chapter mechanic. At this point he is stymied with this as wevar He has visited here several times and we talk almost daily.

[jg61hawk]

Sponsored Links (Register now to hide all advertisements)

Post 4 in the below thread is the link to JR Bullock. The best money you will spend ( and it ain't much) will be sending him your favorite carburetor to be rebuilt.

As an aside perhaps check the bolts holding carb and intake/exhaust and then try the old trick of spraying some WD-40 or something around the area and see if idle changes (looking for a leak). If it's carb Bullock will fix it.


https://www.fordbarn.com/forum/showt...hlight=bullock

[Mulletwagon]

Had a similar problem which turned out to be sticking/sluggish valves. Sucked some Marvel Mystery Oil in the carb and the problem went away. Now add 4 oz of MMO to gas tank at every fill up. Might check the valve lash if everything else checks out.

[nkaminar]

• Check for vacuum leaks.
• Check compression. I think you may have done this.
• Did you replace the condensor?
• What happens if you turn out the GAV? Better, worse, the same?
• Have your favorite carburetor rebuilt professionally.
• Check timing with spark lever fully advanced with timing light. Should be 28 degrees
• Take off any aftermarket fuel filters or air cleaners, if you have them.
• Squirt MMO in intake while engine is running at a fast idle.
• Adjust valve lash. A special grinder was used to precisely grind the ends of the valves flat and perpendicular to stem.
• If all else fails, take the car back to Ford for a warranty claim.

[700rpm]

Didn’t we go through this in your previous thread on 8/2, and you thought it was solved? What happened? Did you put an original distributor in?

[GerryAllen]

I had something similar. It turned out to be my key switch was shorting on the firewall and would cause the hesitation and hard starting.

[philcobill]

Originally Posted by 700rpm

Didn’t we go through this in your previous thread on 8/2, and you thought it was solved? What happened? Did you put an original distributor in?

The timing gear issue was resolved. The car hesitated before changing the timing gear and continues after it was changed. The engine idles smoothly and quietly, but the sputtering make the car un-driveable. I had suspected carb issues as well.

I only have one distributor, but have several distributor parts (modern and original).

Our local Model A chapter mechanic might come over tomorrow and see if he can help figure out what is going on.

Bill

Walworth.

[700rpm]

Originally Posted by philcobill

The timing gear issue was resolved. The car hesitated before changing the timing gear and continues after it was changed. The engine idles smoothly and quietly, but the sputtering make the car un-driveable. I had suspected carb issues as well.

I only have one distributor, but have very distributor parts (modern and original).

Our local Model A chapter mechanic might come over tomorrow and see if he can help figure out what is going on.

Bill

Walworth.

Ah. I see. Good luck tomorrow. There’s an answer there somehwere.

[Harpkatt]

Check the fuel,I've found water in my fuel and had similar problems. I took apart the carb and found just a few little drops I cleared the sediment bowl and carb and was good to go. Hopefully its as simple for you.

[J Franklin]

A loose/bad coil wire, or faulty distributor body can cause good idle but poor running at load.

[philcobill]

The local Model A chapter mechanic and I spent the better part of the day troubleshooting the sputtering issue of my Special Coupe.

1. We went through the electrical system starting with the battery cables and going through the ignition system. We tightened connections. There was some mis-wiring in the terminal box which we straightened out. We also cleaned up the ground connections and changed out the lower distributor plate because of a worn out wire.

2. We finely tuned the timing on the distributor. The mechanic used a degree gauge to pinpoint even better timing. I am not sure how it worked, but the engine did idle even better.

3. Checked the cylinder compressions and they were all just below 75psi. This means the engine is still in good condition.

4. We checked out the fuel system from the gas tank to the intake manifold. Don't need to go into a lot of detail, but we tried five, yes five different carburetors and all of them acted the same regarding the sputtering issue. There was sufficient flow and the filters were doing their job keeping the sediment out. In fact, we did not see any sediment in the carbs or the filters. So, because the fuel flow was fine, either all of the carburetors had exactly the same problem (unlikely) or the problem lies elsewhere (more likely).

5. We ran out of time to test the condenser and possibly the coil. This will be done in the next day or two. Is there anything else we can look at?

Results -

1. the engine starts quicker than before,

2. the engine idles nicely but still sputters when test driving or revved up standing still,

3. we pretty much eliminated (fingers crossed) the fuel system/carburetion as the cause of the sputtering issue,

4. the car is still un-driveable, and

5. we have some more things to check out starting with the condenser and coil.


Bill
Walworth, NY

[nkaminar]

Model A mechanics are good to carry in the tool box in the trunk. Be sure to feed them will or they could become cranky.

[1crosscut]

Ask your club mechanic to bring over a different distributor and try it. Yes I know you have gone through yours several times but you haven't switched it out like you have carburetors.

Another thing to try is to bypass the cable from the ignition switch to the distributor.

[jg61hawk]

After 5 carburetor swaps it sure appears to be the spark is breaking down. Be sure the timing rod isn't hitting the # 4 spark plug wire in all it's motion, the rod flips around. I know you mentioned plugs, are they new? Carbon inside the plug or a cracked porcelain is hard to find. # 14 post above is a good place to start. Good luck sorry you got this problem...You got a lot of support.

[Tom Wesenberg]

If the problem is electrical, I've seen poor contacts in ignition switches, switch terminals hitting the gas tank and shorting out, dirty or loose connections inside the terminal box, distributor bodies shorting, mostly between #3 and #4, bad popout wires at the distributor end, and shorting lower plate wire in the distributor.

[philcobill]

I think I may have fixed the problem of sputtering. I simply replaced the condenser and it is no longer sputtering. What bothers me is that the condenser that was apparently "bad" was a "new" one from one of the Model A online stores. Is there a problem with quality control on these condensers?