Sears Marvel 2405

[Ruth]

JBill, have you tried Dave Renner?

[Ruth]

JBill, have you tried Dave Renner? www.rennerscorner.com If he doesn't have what you need new he sells used parts. I have gotten a couple of good throttle shafts from him.

[ndnchf]

Originally Posted by JBill

I have run a Marvel in the past and probably would again if I could find the fitting mine required at the carb inlet in order to adapt it to a standard Model A fuel line. I haven't seen this mentioned. Was (is) mine just weird? The inlet on my Marvel is not the same size as on any of the half dozen Tillotsons or Zeniths that I have.

Renners Corner sells the fitting. Part number
9288-FLA. I just got one.

[ndnchf]

One thing to note. The original Marvel fuel line adapter came with a strainer. The adapter from Renners does not. So you'll want to incorporate a sediment bowl or something similar.

I have a Marvel on my A now and love it. But I also have another, freshly rebuilt Marvel ready to install. I was going to put a glass bowl under the '31 style fuel shut off. But instead, I'm now adapting a '31 Zenith side sediment bowl to the Marvel. It is smaller and makes for a cleaner looking set up.

[Dick M]

You can call the folks in post #18. They have the fitting...

[The Master Cylinder]

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Originally Posted by Ruth

JBill, have you tried Dave Renner?

Originally Posted by Ruth

JBill, have you tried Dave Renner? www.rennerscorner.com If he doesn't have what you need new he sells used parts. I have gotten a couple of good throttle shafts from him.

Originally Posted by ndnchf

Renners Corner sells the fitting. Part number
9288-FLA. I just got one.

Originally Posted by Dick M

You can call the folks in post #18. They have the fitting...

I'l bet Dave Renner at Renner's Corner has what you need??

[Rob Doe]

Originally Posted by legacy

I have a 1928 Ford Model A Tudor with a Tillotson carburetor.
The car stalls when I come to a stop, causing some very stressful situations, like blocking a lane of traffic while I try to get the car started.

Legacy, I've attached a write up that I've been adding to for some time regarding your problem. While it is Zenith oriented, much of the info still applies. Near the end, there is a tip regarding how to determine if the problem is in the carb. I sure hope it helps you. Rob

Model A Stalls At A Stop But Restarts Easily

Our ’31 coupe has a Bert's rebuilt Zenith carb on her. Her short driving history is clouded by a fresh motor that was breaking in and a new Model A owner. After 6700 miles Little Bug Eye idles nicely after a warm up and does not normally die at stop signs. I glance at the ammeter as we come to a stop, especially at specific corners where during break in, she did die. Her ammeter flickers widely, warning of an imminent stall. A quick adjustment of the hand throttle preempts this. My feet are occupied with the clutch and brake pedals.

The jury is out on what causes this rarity. Sometimes I lean under 1/4 turn GAV setting when in open country and forget to reset to 1/4. I believe a setting at 3/8 might stop this, but when checked, my plugs are a dry gray rather than tan; so, I don't like 3/8. One stop where Little Bug has struggled is a down hill grade from higher speeds. Hard braking warrants an eye on the ammeter.

Edit: I had opened my Idle Air Adjustment screw an extra turn to see if my plugs would change to dry tan. And promptly forgot about doing this. I have reset the base idle to 1 1/4 turns open and cannot force the car to die at a stop.

Below is a list of tips collected from knowledgeable sources. I’ve tried to sequence them logically. For purposes of this writing, the car is assumed to be at home, in the garage or out on the driveway. For sake of brevity, it is assumed that the engine’s cylinder compressions, valve train, cooling system etc. are performing satisfactorily.

Preliminary Electrical and Ignition Specific Checks:

A high percentage of Model A drivability problems are found to be electrical. Some say as high as 90%. Your car’s electrical system must be functioning properly.

Before declaring that your stalling issue is carb related, check the basic electrical circuits / components first, using proper voltage testing procedures. The Les Andrews (blue) book, “Trouble Shooting and Diagnostics,” has instructions with ‘how to’ sketches for the important voltage tests. These tests take only a few minutes to accomplish, and they will identify loose or corroded connections and failing components.

A failing battery can wreak havoc on the charge system. Low battery voltage causes weak ignition spark, so can a failing coil, dirty plugs, a loose or damaged high tension coil wire, reverse coil polarity, dirty points, incorrect point or plug gaps, incorrect timing, faulty distributor component grounds. A dirty, too loose or too tight ignition cable ferrule where it is screwed into the side of the distributor can also cause issues. Weak or intermittent ignition function will exacerbate ‘stalling on stop’ issues.

Remove the safety fuse or unhook the battery ground cable. Verify all electrical connections are clean and tight, from the battery ground connection at the frame cross member, to the starter switch, to the junction box, up to the ammeter and all the way to the generator cutout and its input side where it connects to the generator internals. Consider using Kopr Shield to coat clean, bright metal, contact surfaces to limit corrosion issues for long periods of time.

Carburetor Specific Checks From Many Different Sources

Check for air leaks at the throttle plate shaft, the carb to intake manifold connection, the intake manifold to block connection and the vacuum wiper connection, check for pinholes in hoses or lines etc.

Base Idle Air Mixture screw needs adjustment. (This worked for me.)

Base idle speed is too high, allowing GAV to have too much effect. The Berts rebuilt carb on our coupe was set at 470 rpm with spark advance at 25%, GAV 1/4 turn open. I’ve also seen 1/8 turn open suggested.

Float is free, level on three sides and moves straight up and down. It must not rub against the bowl. Some bowls have bumps or seams that protrude.

Carburetor is dirty. Stalling on stop is likely the idle circuit or the compensating circuit components. (compensator jet, idle jet, secondary well, cap jet, GAV are dirty, jets can be loose and leak at their base too.)

Throttle plate not closing off entire throat when idle screw is backed off the stop. Use a penlight to diagnose looking for gaps. Loosen screws and adjust by closing plate firmly a few times, then tighten the two hold down screws.

Throttle plate has incorrect angles at the leading and trailing edge. 18.5 deg. or it may be installed incorrectly. Check angles.

Secondary well (brass insert) does not have a machined relief aligned with the compensator jet.

Compensator jet extends too far into the compensating well.

Float setting is incorrect, hanging up intermittently or is sticking open or shut.

Flow rates on one or more jets are outside established guidelines.

A Tip to Help Diagnose If Stalling is Fuel or Ignition Related

I watch the ammeter as my toe pushes the starter button. If I don’t see the ammeter twitch with each cylinder compression, I stop and install the safety fuse, open the fuel valve or turn the key on! This twitch is referred to as the “Henry Jiggle”. IMHO, ‘driver’ Model A’s should have the November 1929 Service Bulletin wiring change applied, so the primary ignition circuit function is reflected on the ammeter as a negative twitch at low rpms. If your car stalls on the road, or when approaching a stop, before pushing in the clutch, check for Henry’s Jiggle.

If the jiggle is there, the primary ignition circuit is very likely working as it should. Check the secondary circuit spark quality at the coil wire. If Henry’s Jiggle isn’t there, perform primary ignition circuit test procedures as covered in the Les Andrews blue book mentioned above. Your ammeter is your friend. Check it before exiting your A. It should not show a discharge.

[daren007]

I have been rubbing a Tillotson for years without problems.

[The Master Cylinder]

Originally Posted by daren007

I have been rubbing a Tillotson for years without problems.

I hope you don't rub it in public!!

[ModelABum]

This is an old post, but in case any one else is looking, I just bought an adapter at Ace Hardware. You need to take the carb and a Zenth/Tillotson connector and they can match them up.

[Joe K]

Originally Posted by JBill

I have run a Marvel in the past and probably would again if I could find the fitting mine required at the carb inlet in order to adapt it to a standard Model A fuel line. I haven't seen this mentioned. Was (is) mine just weird? The inlet on my Marvel is not the same size as on any of the half dozen Tillotsons or Zeniths that I have.

Marvel variants, most of them anyway, are made with a "plug" which allows one to align to the Model A fuel line (side) or the Model B fuel line (front)

That said, a small number of Marvels have only the Model A side plug - and the front position is "blank" - but could be drilled/tapped for the Model B.

I believe this side plug is 1/8" pipe thread - which indeed does require a brass compression fitting to bridge the gap.

This "single connection" Marvel has been said on this board to be superior to the double connection in having a "power tube" akin to the Tillotson F1A/B.

I own both Marvel types and see little difference. And little resemblance to the F1A/B.

Joe K