Sisson choke wiring question

[37silverstreak]

Hey everyone,

It's been quite awhile since I've posted anything here. Last fall I picked up a nice original 1949 Plymouth P18 4dr. I've been working on it when time and money allows. The original Sisson choke was missing and the previous owner had hooked up a manual choke cable to the carb. I've installed a NOS Sisson choke, but am trying to figure out the routing for the wire. The wiring schematic shows the wire mounting to the starter terminal but I would like to know if there is a certain way the wire physically routes to the choke? Anyone have any pictures or input? Thanks!

Kevin

[Doug&Deb]

I’m at work so I don’t have the car with me but I believe the wire mounts on the starter to the same connection that the wire coming from the solenoid connects to. The choke operates when the starter engages. A heavy gauge wire runs from the starter to the choke. It’s grounded by the mounting bolts. Make sure you put a heat resistant gasket under the choke assembly or it will burn up ( don’t ask how I know).

[DonaldSmith]

When the engine is cold, a bimetallic spring within the Sisson choke partially closes the choke plate in the carb.     

While the starter is engaged, the Sisson choke electrically closes the choke plate an additional extent. 

Once the engine is started, it doesn't need this additional choking; as the engine warms up, the bimetallic spring gradually opens the choke plate completely. 

 

The starter solenoid incorporates a heavy-duty switch to connect power from the battery to the starter. 

Now, as I'm looking at the engine end of the starter solenoid, the lower right post is the "hot" post, connecting the cable from the battery to the heavy duty switch inside the solenoid housing.  This post also connects other circuits to the battery: formerly red wire to circuits at the instrument panel, and formerly green-and-black wire to the horn relay. 

 

The upper right post has the formerly black-and-yellow wire from the starter switch.  This powers the solenoid windings.  

 

The upper left post provides the ground to the solenoid windings.  This post has a formerly brown wire going to the to the generator, or if an alternator replaces the generator, this wire goes to a convenient ground.  (When the engine is running, the generator does not provide a ground, saving accidental engagement of the starter.  Clever.) 

 

The lower left post connects the other side of the heavy-duty internal switch to the Sisson choke.   This is where you connect your Sisson wire. 

 

Pressing the starter switch provides power to the upper right post, and through the solenoid windings to the ground at upper left.  This energizes the solenoid winding and closes the internal switch.  This connects the power from the battery (lower right post) to the starter itself, which is grounded to the engine, and to the Sisson choke (lower left post), which is grounded to the manifold. 

 

[Plymouthy Adams]

I'm disappointed, NOT going bluetooth and get an app to operate the choke from your smart phone......?

[chrysler1941]

1 hour ago, Plymouthy Adams said:

I'm disappointed, NOT going bluetooth and get an app to operate the choke from your smart phone......?

Or an app for remote start

[plymouthcranbrook]

And don’t forget the app to push the clutch in and shift into neutral.

[Sniper]

No one really answered how the wire is physically routed.

 

 

[allbizz49]

The wiring on my 53 is still original. The choke wire runs from the starter to the choke across the top of the engine. The wire itself is cloth covered and it has a protective cloth covering over it that you can see is fraying. I have to figure that is for extra protection against the engine heat. Hope that helps.

[37silverstreak]

4 hours ago, allbizz49 said:

The wiring on my 53 is still original. The choke wire runs from the starter to the choke across the top of the engine. The wire itself is cloth covered and it has a protective cloth covering over it that you can see is fraying. I have to figure that is for extra protection against the engine heat. Hope that helps.

Thank you ALLBIZ49, that is just what I was looking for! 

[chrysler1941]

You probably already solved it but for the record, my 41's choke wiring is part of original loom. From choke up to firewall, hooks on a clip on head (removed here for clarity) meets wiring from carburetor, goes around engine via firewall clips and behind starter.

 

Edited May 24, 2021 by chrysler1941

[harmony]

When it comes to adjusting your new choke assembly, it's a piece of cake to make your own tool to set the sisson choke.  The closest rod diameter I had kicking around was 3/32" dia. which is just slightly larger than the original tool so I filed and sanded it until I got the perfect fit.  

[Sniper]

Drill bits work, that's what I used, 5/64" which is a hair under 3/32".

 

Edited May 24, 2021 by Sniper