choke solenoid types

[slx12001]

Looking over some electric choke solenoids and wondering what the differences are. I see single wire with ground and dual wire with ground. I looked at the wiring schematics for several years and is seems the dual wire with ground type are wired different ways. Some run the second "hot" wire in series and some have the 2 wires going to separate places. Are the 2 wire with ground a single coil with 2 wires coming out for more power or do the 2 wire with ground have 2 separate coils? If so why? I need to replace a 2 wire with ground solenoid and all that I have here is 1 wire with ground. Thanks for any help.

 

[jbuote]

Not a pro, but I think it's just 2 wires to one coil inside..
One wire would go to choke switch (toggle or push to choke on ignition) and the other to a thermal sensor to provide choke when cold until warmed up.
My 71 50 hp had the thermal switch, but it was cut out and uses only the choke toggle...

In short, I'm pretty sure the 2 wire 1 ground solenoids are simply to allow 2 different methods of actuating the choke..
Again, not a pro, so I look forward to other comments because If I'm wrong then I get to learn something here too!

Hope it helps

 

[slx12001]

Thanks for the reply. I just took a closer look and yes the second wire goes to a thermal switch. I'm going to strongly assume there is a single coil with 2 wires. Not sure why they would not simply put a jumper at the other end though.

 

[racerone]

I think there are 2 coils in there.

 

[F_R]

OK, here's the scoop. They had a dual-winding solenoid with two hot wires, one to each winding, providing two choke stages. The first stage was energized by the thermal switch as soon as you turned the key on (cold motor). That provided a partial "warm-up" choke to keep it running till it warmed up a bit. But, being only a partial choke, the second stage was needed for a full choke for startup, energed by a switch by the driver. With both stages energized, the choke was slammed tight shut for easy cold starting.

Sound good? It was. Except under certain conditions, the warm-up choke might be on and cause hard re-start if it was shut down. So....a service bulletin was issued, instructing dealers to re-wire it so BOTH stages are energized by the driver, and the warm-up function was disabled.

Later models had only one stage, one hot wire, and energized by the driver only. No warm-up thermal switch.

 

[F_R]

[No message]

 

[jbuote]

Well that makes sense! Thanks F_R!! Always good to learn something each day...

So for the OP who wants to replace a 2 wire solenoid and only has a 1 wire solenoid... They can do that since the 1 wire solenoid would be for the switch (operator controlled) and it wouldn't have that partial coil in it anyway, so the thermal switch will be left disconnected..

There's no real reason to get a 2 wire solenoid UNLESS a person intended to hook up the thermal switch and use that as well as the operator control.
Not sure why one would do that since a bulletin came out basically removing it though...

Would that be correct info for the OP?

 

[F_R]

Yes

 

[slx12001]

Thanks for the replies. Very good info about 2 wire chokes solenoids.