DHSA2 to DFEV Carb Swap

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s0uf2k
Posts: 2
Joined: Thu Jun 25, 2020 6:29 pm
Your car is a: 1972 Fiat 124 Spyder

DHSA2 to DFEV Carb Swap

Post by s0uf2k »

Hello everyone,
I have a ‘72 Fiat spider 1600 and my DHSA2 carb has been giving me too many problems so I have purchased a Weber DFEV as a replacement. I have a manual choke on the DHSA 2 and the DFEV is an automatic choke. Is there any info on how to properly hook up an electronic choke and is there any modifications that I need to know/be aware of before i tackle this swap?
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: DHSA2 to DFEV Carb Swap

Post by 18Fiatsandcounting »

The way the electric choke works is that it has a bimetallic strip in it, shaped into coil. When +12v is applied to the choke, the coil slowly (several minutes) unwinds and opens the choke plates. So, what you need is a source of 12v that is only active when the ignition is on.

Before swapping the carbs, I'd verify that the choke is working. Use your car battery to supply the 12 volts, and the choke plates should be closed before you connect the battery, and then the choke plates should slowly open after a few minutes of current flowing. You may have to slightly open the throttle by hand periodically to allow the choke cam/lever to open.

As for finding a source of switched 12 volts for the choke? Could be almost anything, but if you tap into the fuse box on a circuit that is only active with the ignition turned on, that would probably work. Others with more experience with this might have a better suggestion.

-Bryan
s0uf2k
Posts: 2
Joined: Thu Jun 25, 2020 6:29 pm
Your car is a: 1972 Fiat 124 Spyder

Re: DHSA2 to DFEV Carb Swap

Post by s0uf2k »

Thanks for the reply Bryan!
Your response was insightful and informative definitely will help in retrofitting my choke!
73CS1592
Posts: 28
Joined: Fri Sep 06, 2019 8:06 pm
Your car is a: 1973 CS

Re: DHSA2 to DFEV Carb Swap

Post by 73CS1592 »

s0uf2k wrote:I have a manual choke on the DHSA 2 and the DFEV is an automatic choke. Is there any info on how to properly hook up an electronic choke and is there any modifications that I need to know/be aware of before i tackle this swap?
You can also convert the DFEV carb back to manual if you want to keep the originality of the choke, which I personally like.
Here is the link to the part. Maybe someone else carries it... I'm not affiliated to them :D

https://allisonsautomotive.com/products ... 281e&_ss=r

Cheers
Last edited by 73CS1592 on Thu Sep 03, 2020 7:03 am, edited 1 time in total.
SteinOnkel
Posts: 1000
Joined: Tue Feb 19, 2019 9:31 pm
Your car is a: 1978 124 Spider 1800

Re: DHSA2 to DFEV Carb Swap

Post by SteinOnkel »

That's awesome! I love manual chokes. No idea why we got rid of them, they always work.

I wonder if it would fit my 34ADF. Is it hard to source the knob and cable for the choke? How does it attach in the dash?
73CS1592
Posts: 28
Joined: Fri Sep 06, 2019 8:06 pm
Your car is a: 1973 CS

Re: DHSA2 to DFEV Carb Swap

Post by 73CS1592 »

SteinOnkel wrote:I wonder if it would fit my 34ADF.
Supposed to. Buy it and let me know :D
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manoa matt
Posts: 3442
Joined: Thu Oct 26, 2006 4:28 pm
Your car is a: 1978 Fiat 124 Spider 1800
Location: Honolulu, Hawaii

Re: DHSA2 to DFEV Carb Swap

Post by manoa matt »

Stein, What's wrong with the water activated automatic choke on the 34ADF? Never had an issue with one. BTW if you look under your dash, you might already have the cable. There is a knob that says "throttle" and is a crude cruise control mechanism. The knob and cable should be attached to the throttle and when you pull it out and twist it, it locks in place.

To convert the carb to manual choke, simply remove the water housing. There is a forked bracket that engages the bi-metal spring. You would hook your cable to that bracket.
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