Choke Question

[76SeaRay]

I am planning at this point to go to a 97 to 99 vortec engine with my restoration. I plan to use a carbureted system on it. Right now I am redesigning and remanufacturing my helm instrument panels. I assume that I should add a choke button to the panel to operate an electric choke. Anybody have input on typical switches and set up as well as the carb setup with an electric choke?

Thanks.

 

[alldodge]

The electric choke is powered ON when the ignition key is turned to ON. The purple wire which powers all circuits is also connected to the electric choke. When cold the carb choke butter fly closes when the throttle is pumped at least once, After the engine starts the power going to the choke slowly opens it.

There is no switch needed or required like on an outboard

 

[Scott Danforth]

AD has you covered. normally the electric choke is daisy chained off the +12 volts going to the coil.

 

[76SeaRay]

Great, thanks for the info... One less switch on the instrument panel then....

 

[QBhoy]

As above....but worth noting it isn’t required at all. Most where I live have been disconnected after a certain age. Tend to fail a fair bit causing flooding or other problems.
Gotten round by pumping the throttle about 8-10 times before a cold start and feathering the throttle on warm up

 

[Scott Danforth]

As above....but worth noting it isn’t required at all. Most where I live have been disconnected after a certain age. Tend to fail a fair bit causing flooding or other problems.
Gotten round by pumping the throttle about 8-10 times before a cold start and feathering the throttle on warm up

or for 3 minutes worth of maintenance every few years you can keep it running like new.

 

[Lou C]

Ahh, you want to the choke to work and it ain't rocket science. Those of us of a certain age who grew up with cars that had carbs n chokes can tell you they don't take much to be kept working properly.
1) good thermostatic spring
2) clean choke plate and linkage
3) functional source of heat to open the choke, whether its exhaust heat or electric
4) functional vaccum break or choke pull off
5) proper adjustment.

Now that wasn't so hard was it?
The reason why we know how to make chokes work is because while your boat may start at 60* F with no choke, your car sure as hell ain't starting when it's close to zero unless you got a working choke.

PS, pumping it 10 times can flood the engine and also wash gas off the cyl walls. The choke was designed by engineers who know how much extra fuel the engine needed to keep running during a cold start. They just need a backyard mechanic who knows how they work and how to fix it when its not working.

 

[QBhoy]

Ahh, you want to the choke to work and it ain't rocket science. Those of us of a certain age who grew up with cars that had carbs n chokes can tell you they don't take much to be kept working properly.
1) good thermostatic spring
2) clean choke plate and linkage
3) functional source of heat to open the choke, whether its exhaust heat or electric
4) functional vaccum break or choke pull off
5) proper adjustment.

Now that wasn't so hard was it?
The reason why we know how to make chokes work is because while your boat may start at 60* F with no choke, your car sure as hell ain't starting when it's close to zero unless you got a working choke.

PS, pumping it 10 times can flood the engine and also wash gas off the cyl walls. The choke was designed by engineers who know how much extra fuel the engine needed to keep running during a cold start. They just need a backyard mechanic who knows how they work and how to fix it when its not working.

Understood. Choke operation also over fuels, hence the black smoke on start up. 6 and 2 3’s I say. Choke is a convenience to aid starting, but not essential.
If I was using through winter....yeah I’d likely have kept it. Just that here in Scotland the constantly changing from damp and cold to warm and back again means that condensation ensures an unreliable operation of these chokes. They are widely disconnected over here.

 

[Lou C]

Keep in mind I have lived in the damp Northeast USA my whole life. Temps ranged from close to 100 F in summer to slightly below zero in winter. Have had the following cars with carbs n chokes, and made them all work reasonably well:

1965 VW Bug and 1956 VW built into Dune Buggy in the 1960s, owned it in the early 70s, had one good 1200 cc engine between them lol 1 bbl Solex choke electrically heated.
1970 Ford Torino 302 cu in (5 ltr) with Autolite 2100 2 bbl exhaust heated choke
1972 Chevrolet Impala 350 cu in (5.7 ltr) Rochester 2 bbl, intake manifold heated choke via exhaust crossover
1975 Olds Delta 88 350 cu in (5.7 ltr) Rochester 4bbl same as above
1980 Honda Civic 1335 cc, 3bbl Keihin carb, electric choke, this one never ran quite right but the choke was not the problem, it was Honda's imperfect adoption of the CVCC system to avoid cat converters that was the problem
1982 Mazda 626, 122 cu in (2 ltr) 2bbl carb, auto choke worked fine on this one.

Boat, 1988 F/W 4.3 V6 with Rochester Quadrajet, intake heated choke. It works exactly as designed, all you need to do is make sure that the thermostat is not sticking because that prevents full engine warm up and clean the choke shaft and and linkage once at the beginning of the season. After the initial start up of the season, it lights off instantly on cold starts.

If you get black smoke, your choke is not set right. Either the choke pull off is not pulling it open enough, or your float is close to flooding the engine. Black smoke is not normal choke operation and none of the cars listed above did this when I was running them. Without a proper functioning choke, after a cold start you get a rough running engine that is on the verge of stalling which is dangerous in a vehicle or boat. Stalling vehicle engine you lose your power steering and brakes, but can stil steer or stop. Boat, you lose your ability to stop completely. A mechanic who disconnects a choke because it does not work right has not fixed anything, or has failed to understand how it was designed to work and just gave up.

Example:
Ford 302 above. Bought used, realized choke was very slow to open up. Tried new thermostatic spring, same result. Did some checking, realized choke spring is heated by hot air, sucked past spring, via a vaccum port. Used a bit of motor oil in a squirt can on choke linkage. Realized that the choke linkage shaft was letting in air, that diluted the heat from the exhaust manifold. Fix was removing choke linkage and fitting fiber washers on either side of shaft as bushings to seal vacuum leak. Choke worked 100 % after that. Tried fitting a manual choke kit to it. I was the only one in the family who could get the car to start in winter with that set up! So you see, you just need to be a real mechanic.

 

[San_Diego_SeaRay]

For what it's worth I recently came across a similar dilemma. I bought a new carb that came w. an electric choke when the previous one was mechanical. Mine is a 1993 Mercruiser 7.4 300HP. Instead of wiring off of the coil, I decided to run a wire from the alternator so that amps are not pulled off the ignition circuit. My alternator has - and maybe most have - a post that produces a separate "positive" from the charging positive. This way, it does not tie back to battery off the main starter post. I'm not a great mechanic nor an electrical expert so I'm not sure my logic makes sense, but I thought that having the choke tied into a circuit that only is active when the engine is turning was the best option.

 

[76SeaRay]

Been away for a while. I was just at a swap meet and picked up a rebuilt (including new bushings) marine Rochester quadrajet. It has an electric choke on it. So, wanted to post the final result. I will be wiring it to the coil as suggested above.

 

[Lou C]

Something to keep in mind. There are different types of electric chokes that have been used over time. Some are designed to operate off of only 6-7 volts, some need a full 12 volts to open fully. So if you use the coil as the source of power, and the choke needs a full 12V to operate, it may not open fully. Check the back of your alternator when the engine is off. You don't want any terminals that have power with the engine off. Then check it with the engine running, try to find one that gives charging voltage only when the engine is running, if it needs a full 12 V. I know that both Holley and Edelbrock carbs need 12V at least to open the choke.