No Choke Cable

[WillM]

The A4 in my '76 Ranger 33 lacks a choke cable. Are others aware of A4 installations without a choke cable? I have not had any trouble starting it in the three years since I have owned it until last month. It had started easily 2 weeks prior to that. After several hours of troubleshooting with no results, I re-read the manuals and noted the need to choke the carb when starting the A4. I have never had to do that before, so I assumed it had an automatic choke. Obviously I was wrong about that and I located the choke lever and hand-held it closed...it started and ran smoothly as it has previously. I can easily add a cable, but it seems strange none was required before.

[hanleyclifford]

It would be interesting to know your rate of fuel consumption over the three years. Your circumstance is new to me. Also, what did the spark plugs look like?

[JimG]

On my 76 R33, the choke cable leads to the sidewall just above the port cockpit drain. Check for a filled hole or other trace. I can't imagine mine starting easily without the choke, although I can usually open it after 10-15 seconds of running.

[roadnsky]

Well, obviously you'll need to add a cable since with with a clean carb and proper timing, the carb should be choked to start.
Here's an educational post from Don about choke settings and the A4...

"Most "naturally aspirated" carburetion systems (before the advent of fuel injection and superchargers) have two features designed to facilitate starting: they have some method of closing off (hence the term choking) the incoming air stream to the carburetor so that fuel will be drawn from the float chamber into the intake manifold, and a small piston pump which provides a small squirt of fuel directly from the float chamber into the intake throat of the manifold whenever the throttle was advanced. In addition to aiding in starting, this pump also improves the acceleration of the engine, hence its name "acceleration pump".

As an engine warms up and generates enough air flow through the throat of the carburetor and intake manifold to supply a proper fuel/air mixture into the combustion chambers, the choke valve can be slowly returned to normal (open).

The reason it's so critically important that the choke valve be completely closed for an Atomic 4 to start reliably is that it uses an "up-draft" designed carburetor. In an up-draft system, the carburetor is below the inlet to the manifold which means that the fuel/air mixture must be drawn uphill to pass through the carburetor and up into the combustion chambers.

Acceleration pumps are not practical in an updraft carburetion system, which further underscores the need for a properly adjusted choke on the Atomic 4.

On the plus side, it's practically impossible to flood an updraft carburetor. Even in cases where raw fuel might be puddled in the bottom of the intake throat of the carburetor, it's still necessary in most cases to choke the engine for a quick start."

When did you last clean/rebuild the carb?
As Hanley asked: "How do your plugs look?"

It's certainly an interesting scenario...

[wlevin]

Choke for how long?

Reading these posts made me wonder what how other A4's act compared with ours with respect to choking. For years our engine would start immediately with full choke, then the choke could be pushed in completely right away and it would idle fine. These days I have to start with full choke then return it slowly to pushed in position. If I do it too quickly, the engine will die.

First, is this what others in the group normally do? And second, can the carb be adjusted better?

Our choke does open and close fully. Also, we just installed the Indigo kit for dealing with blow by and I've been messing with the idle adjustment since.

Bill and Jeanne
T34C #453
Otter

[ndutton]

Full choke to start, fires within 1 second of cranking regardless of how long the layoff, choke full off within 2 seconds. Life is good.

Last carb rebuild was 2 years ago.

[67c&ccorv]

Get yourself a choke cable and hook it up.

[wchevron]

1978 A4. Pull choke for start-up, after 30 sec. full off. Once the engine is warmed up, may need to only pull choke for 1-2 seconds only.

[Baltimore Sailor]

1975 A4, rebuilt by MMI in 1993, head gasket and carb replacement by me in 2008. Full choke to start, push choke in after about 10-15 seconds (about as long as it takes me to take a good look over the transom at the water flow).

On Saturday I sailed for a good 2 1/2 hours after shutting off the engine, and it restarted within two seconds with the choke still in.

I love that little engine.

[WillM]

Well, A4 started perfectly last weekend. I ran it for extended time frame (30 minutes) with no troubles. Sailed 2 hours and it restarted without difficulty allowing return to the marina. Tonight, it started (without choking), but only ran for 3-4 minutes and then stopped. It refused to start thereafter. Dirty carb vs. electrical now seems more likely.

[smosher]

3 - 4 minutes sounds more like a sticky float

[sastanley]

My choke experience (after I got the cable adjusted to fully close the choke) has been full choke to start, not quite as quick as Neil's, but usually within 5 seconds, 1/2 choke for about 2 minutes, and then choke open and usually no problem.