Engine sputtering

[Jacked up]

Hello, Folks
Lola, my 29 Tudor, runs fantastic on flat roads and when climbing hills. When I drive down a long, sleep hill in 2nd gear, she pops and spits, but does not backfire. I have leaned out the gas with the dash adjustment knob, and I have changed out the float washers in the carb, thinking that the tilt go the car going downhill was making the engine burn rich.
I would appreciate any and all feedback. I'm a newbie, and I follow the forum everyday. I appreciate the support and expertise of members.

[Sunnybrook Farm]

They will kind of do that if you put the spark up, could be timed a little slow, how does it run on flat road?

[Jacked up]

She runs great on flat ground.

[goodoldvic]

It sounds good to me, how steep? maybe weight of your car is bucking the idling engine

[H. L. Chauvin]

First, what type of carburetor; Zenith?

If Zenith, the round bowl, on an abrupt stop, will many times cause flooding and will kill a very slow idling engine.

The later Model A repro "Marvel" carburetors, (sold by Sears at one time), with 90 degree corners in the bowl usually never flood and kill a slow idling engine on an abrupt stop.

Simple Test: Next time going down hill, with GAV fully "closed", and engine "popping and spitting", try opening your GAV one (1) full turn to "experience" if there are any changes.

If "yes", good chance rich fuel related ...... try lowering fuel in bowl by adjusting float per the Mr. Rex Reheis dimensions and method.

If no changes, very possible "not" fuel rich related.

Let us know what ?????? many ears waiting.

[Jerry in Shasta]

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A wise man said that "80% of fuel problems are electrical". Go back to the beginning, do a compression test, timing, point gap, etc.

[VFRhugh]

Although I've changed to a Marvel I was having lean issues and stalling on sudden stops with a Tillotson. Since I had a good running car with the Marvel I dove into the Tilly. Turns out the flange to manifold was warped along with the upper and lower body flange. I used wet or dry sandpaper to level both surfaces. Put the Tilly back on my A and it runs great. Not as good as the Marvel but dramatically better.

[H. L. Chauvin]

Model A carburetors and MPG results for same are interesting.

Other than Marvel carburetors being made with pot metal, and not looking "original" on a Model A for Judging Standards, they appeared to function quite well on sudden stops and MPG when new.

After getting my 1930 Coupe in 1958, I was averaging 28 MPG with the former mechanic/owner's "untouched" new marvel that came with my 1930 Coupe, while traveling in rural areas using non-plug-fouling unleaded Amoco gas.

This Marvel never caused problems on sudden stops or steep down hills. Still have it.

One day I will try this Marvel on my 1930 Town Sedan, now averaging 20 MPG with a 1932 B carburetor. Never checked MPG with my several spare Zeniths & Tillotsons.

Many often get discouraged after one gives Model A results for MPG for City Driving and Rural driving and sometimes with different "Stop & Go" Traffic Results; however, in not being very specific, Model A MPG results have been experienced by many to have varied for example with:

A. "Stop & Go" Traffic in "Urban and Suburban" areas where it may mean stopping at every street corner at a Stop Sign or Red Light; and/or maybe combined with,

B. "Stop & Go" Traffic in "Semi-Rural/Rural Areas" where it may mean stopping at every intersection and/or junction at a Stop Sign or Red Light located from for example one (1) mile to maybe thirty (30) miles apart; and/or maybe combined with,

C. Either gentle and/or steep hills compared to flat land, plus many other variations such as vehicle weight, numbers of passengers, etc., etc.

Always good to try to compare apples to apples when considering MPG.

[Mitch//pa]

You ever do a wash and wax then recheck the MPG

[H. L. Chauvin]

How about four (4) more detailed, separate Model A MPG tests:

1. Side windows down/windshield open; vs.,

2. Everything buttoned up, vs.

3. Against the wind, w/1. & 2., vs,

4. With the wind w/1. & 2.

5. Uphill/downhill ???????

With lower gas prices, Model A MPG has become one of the Forums last on the list concerns ............ but let us just wait ............ it will raise eyebrows again if we live long enough.

[Mitch//pa]

I never check fuel mileage on my cars modern or old,,,....as long as they run perfect and I get a good burn on the plugs, (no fuel leaks) I'm happy and know it's getting the best possible.