4V Choke electrical voltage

[BigBrother-84]

The cam eccentric is what actuates the fuel pump lever so if the engine isn't turning the pump isn't filling the carb.

Certainly, when stone cold one press of the pedal will set the choke.

If there's still gas in the primary bowl, multiple pumps of the pedal will push raw fuel into the plenum and provide the very rich mixture you need for the engine to catch (because the fuel doesn't want to atomize and condenses on the floor of the intake manifold)

If the truck sat long enough for the bowls to evaporate, then yes there's nothing for the accelerator pump to push.

Pumping like mad will be sure to catch those first drops and get them into the intake.

This is the reason for the exhaust crossover that heats directly under your carb.

Obviously the engine has to get running for that to have any effect....

Capiche, thanks Jim.

Now, let's dig little further with the choke voltage question... Here are some picts I took of the old and new carbs.

Three questions:

1- Caps voltage:

But the real question is what the black plastic choke heater says. 12V?

Well, there is no such indication on the two caps. Do I look correctly?:

2- Caps swapping:

Why not just use the Holley choke cover for the 4180? It is made for the 7V supply.

I canot figure out how the old one could fit on the new carb... Maybe I suffer of a lack of creativity?

And the new one appears to be much easier to adjust... I am wondering how to adjust the old model? Never done it...

3- Relay solution:

The relay setup works well on the Edelbrock on my 351W, pulled in by the stator wire.

Could a relay add-on be a simpler solution? If so, any suggestion about such a relay and how to wire it?

Thanks again Gentlemen!

 

[ArdWrknTrk]

Capiche, thanks Jim.

Now, let's dig little further with the choke voltage question... Here are some picts I took of the old and new carbs.

Three questions:

1- Caps voltage:

But the real question is what the black plastic choke heater says. 12V?

Well, there is no such indication on the two caps. Do I look correctly?:

2- Caps swapping:

Why not just use the Holley choke cover for the 4180? It is made for the 7V supply.

I canot figure out how the old one could fit on the new carb... Maybe I suffer of a lack of creativity?

And the new one appears to be much easier to adjust... I am wondering how to adjust the old model? Never done it...

3- Relay solution:

The relay setup works well on the Edelbrock on my 351W, pulled in by the stator wire.

Could a relay add-on be a simpler solution? If so, any suggestion about such a relay and how to wire it?

Thanks again Gentlemen!

Like I said above, single bullet Motorcraft choke cap 7ish volts (the black/white stator wire provides about 1/2 the rectified 14ish V alternator output)

Two spade Holley choke cap uses 12V. Because not all brands of vehicle are set up the same way as Ford did it.

As Bill pointed out, the Motorcraft cap would fit right on the aftermarket Holley carb. (This is how my truck is set up)

[ArdWrknTrk]

Capiche, thanks Jim.

Now, let's dig little further with the choke voltage question... Here are some picts I took of the old and new carbs.

Three questions:

1- Caps voltage:

But the real question is what the black plastic choke heater says. 12V?

Well, there is no such indication on the two caps. Do I look correctly?:

2- Caps swapping:

Why not just use the Holley choke cover for the 4180? It is made for the 7V supply.

I canot figure out how the old one could fit on the new carb... Maybe I suffer of a lack of creativity?

And the new one appears to be much easier to adjust... I am wondering how to adjust the old model? Never done it...

3- Relay solution:

The relay setup works well on the Edelbrock on my 351W, pulled in by the stator wire.

Could a relay add-on be a simpler solution? If so, any suggestion about such a relay and how to wire it?

Thanks again Gentlemen!

The documentation that comes with your new Holley carb will tell you the choke cap requires 12V and ground.

You may be confused because the OEM choke cap has a little plastic nub to limit the amount of adjustment (per federal regulations) but it's simple enough to file this back, and then it fits fine in the Holley retaining collar.

 

[Gary Lewis]

Capiche, thanks Jim.

Now, let's dig little further with the choke voltage question... Here are some picts I took of the old and new carbs.

Three questions:

1- Caps voltage:

But the real question is what the black plastic choke heater says. 12V?

Well, there is no such indication on the two caps. Do I look correctly?:

2- Caps swapping:

Why not just use the Holley choke cover for the 4180? It is made for the 7V supply.

I canot figure out how the old one could fit on the new carb... Maybe I suffer of a lack of creativity?

And the new one appears to be much easier to adjust... I am wondering how to adjust the old model? Never done it...

3- Relay solution:

The relay setup works well on the Edelbrock on my 351W, pulled in by the stator wire.

Could a relay add-on be a simpler solution? If so, any suggestion about such a relay and how to wire it?

Thanks again Gentlemen!

Jeff - I think the old carb's choke is a 7V unit. And I think if you take the three screws off it and the one on the Holley they may interchange. But make sure they are both wound the same direction so they open the choke up when getting hot.

As for a relay, it is a fairly simple solution. Below is the wiring on the power distribution box on Big Blue, but it shows how the choke relay is wired. You can put the relay on the fender near the starter relay and pick up power from the starter relay by running a fuse between the relays.

I bought these relays from Amazon and like them 'cause they are nicely sealed. And I bought these fuses, which work out well.

If you are interested I could draw up exactly how to wire it, and it isn't hard to wire.

[ArdWrknTrk]

Jeff - I think the old carb's choke is a 7V unit. And I think if you take the three screws off it and the one on the Holley they may interchange. But make sure they are both wound the same direction so they open the choke up when getting hot.

As for a relay, it is a fairly simple solution. Below is the wiring on the power distribution box on Big Blue, but it shows how the choke relay is wired. You can put the relay on the fender near the starter relay and pick up power from the starter relay by running a fuse between the relays.

I bought these relays from Amazon and like them 'cause they are nicely sealed. And I bought these fuses, which work out well.

If you are interested I could draw up exactly how to wire it, and it isn't hard to wire.

The Motorcraft choke is definitely 7V and it operates in the same direction as Holley.

(note what I said above about the adjustment limiting nub)

IIRC there were some 351 engines that did come with a choke relay....

Here it is from the '86 EVTM

Edit: G801 is shown as behind the LH headlamp

[Gary Lewis]

The Motorcraft choke is definitely 7V and it operates in the same direction as Holley.

(note what I said above about the adjustment limiting nub)

IIRC there were some 351 engines that did come with a choke relay....

Here it is from the '86 EVTM

Edit: G801 is shown as behind the LH headlamp

Good example, Jim. But I think you are suggesting that it would be easier to swap the choke heater, and I agree.

[ArdWrknTrk]

Good example, Jim. But I think you are suggesting that it would be easier to swap the choke heater, and I agree.

In my mind there's a lot to be said for keeping the original set-up, especially as it's been proven to work well (35 years in my case)

I realize that the winters here may not be as cold as Ontario but my choke has worked okay at -20F.

[85lebaront2]

Capiche, thanks Jim.

Now, let's dig little further with the choke voltage question... Here are some picts I took of the old and new carbs.

Three questions:

1- Caps voltage:

But the real question is what the black plastic choke heater says. 12V?

Well, there is no such indication on the two caps. Do I look correctly?:

2- Caps swapping:

Why not just use the Holley choke cover for the 4180? It is made for the 7V supply.

I canot figure out how the old one could fit on the new carb... Maybe I suffer of a lack of creativity?

And the new one appears to be much easier to adjust... I am wondering how to adjust the old model? Never done it...

3- Relay solution:

The relay setup works well on the Edelbrock on my 351W, pulled in by the stator wire.

Could a relay add-on be a simpler solution? If so, any suggestion about such a relay and how to wire it?

Thanks again Gentlemen!

You don't need the metal shell, the retaining ring from the new Holley will work fine. Just start with the reference notch set the same.

[BigBrother-84]

You don't need the metal shell, the retaining ring from the new Holley will work fine. Just start with the reference notch set the same.

Ok Bill, I'm willing to give a try tomorrow. But as a regional doctor operating a delicate surgery not in his qualifications, I'll need to be remotely supervised by a specialized surgeon.

My first "mechanical exploration" was at age of 4. Decided to understand how the hell a Big Ben table clock was working.

Disassembled and opened it when suddenly a spiral spring jumped out of its heart. Was never able to reassemble it, had to apologize to my Mom (with some tears) about this disaster.

I know there is a spiral spring in this cap, I'll have to "hook" it correctly in its new location. Not sure how to do it... Will it jump in my face (again!)?

Will I have to tension it in any ways when reinstalling the cap? If so, how much turn, or turn fractions?

I'll proceed methodically. Will first take out the old cap, examine it, send some picts and wait for instructions.

[Gary Lewis]

You don't need the metal shell, the retaining ring from the new Holley will work fine. Just start with the reference notch set the same.

Ok Bill, I'm willing to give a try tomorrow. But as a regional doctor operating a delicate surgery not in his qualifications, I'll need to be remotely supervised by a specialized surgeon.

My first "mechanical exploration" was at age of 4. Decided to understand how the hell a Big Ben table clock was working.

Disassembled and opened it when suddenly a spiral spring jumped out of its heart. Was never able to reassemble it, had to apologize to my Mom (with some tears) about this disaster.

I know there is a spiral spring in this cap, I'll have to "hook" it correctly in its new location. Not sure how to do it... Will it jump in my face (again!)?

Will I have to tension it in any ways when reinstalling the cap? If so, how much turn, or turn fractions?

I'll proceed methodically. Will first take out the old cap, examine it, send some picts and wait for instructions.

I'm not Bill, but I had the same experience with a clock and knew what was coming when you started down that path. But I can assure you that the spring in the heater isn't going to jump out at you. It is a bi-metal spring, meaning it has two different metals in it, one on one side of the spring and one on the other. And since those metals have different expansion rates that means that the spring will expand or contract due to temperature. But at a given temp the spring is stable.

The best tip I can give you is to ensure that the "hook" at the end of the spring captures the pin of the choke mechanism. I put the heater on the carb with the open side of the hook past the pin and rotate the heater towards the pin to see that the mechanism moves before I secure the heater in place.