DHSA2 Help

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Snowmandopeman

DHSA2 Help

Post by Snowmandopeman »

Hello,
I have been working on restoring my 1972 Fiat 124 spider with DHSA2 Carb, the problem is I know nothing about Carbs besides Go-ped carbs. I need to pull it off the car and rebuild it/clean and tune. Does anyone know how or know of a website that can give me step by step instruction on rebuilding this Carb. Any help would be greatly appreciated.

-Nick
Dougieb
Posts: 129
Joined: Wed Jun 16, 2010 6:37 am
Your car is a: 1972Spider

Re: DHSA2 Help

Post by Dougieb »

Hi Nick,

I have a '72 myself and went through the carb.
It really is no different than rebuilding any other carb.
But that is not going to help if this is your first.
I have some diagrams I can send you.
Give me a day or two to dig them up.

But remember a few things:
Educate yourself first.
I would research "how to rebuild a carburetor" and get good general information before you start.
Knowledge is your best tool.
Try http://www.artigue.com/fiat/ for lots of general information.

Take PLENTY of notes and pictures on everything you do.
This will be invaluable on getting it back together.
Each and every part needs to go back into it's original location.
Have a dedicated space to work on this and lots of cups/bins to sort out the parts.(with notes attached)
Do not rush! Take your time.
Get a good carburetor cleaner tank from a car parts store.
These look like one gallon paint cans but have a good cleaning solution in them.
You will soak your disassembled parts over night (no rubber or brass) usually in two or three batches because of the size.
Get a good can of carb cleaner to wash the parts off after soaking.
Get a good carb rebuild kit like:
http://www.autoricambi.us/product/FU2-4 ... it---DHSA/
Talk to friends that have done this before.

The DHSA is not bad.
But I will say that I replaced mine with a DMSA (and intake manifold) from a '74 and have been MUCH happier.

Good luck, I will see what I can dig up for you.
Dougieb
Snowmandopeman

Re: DHSA2 Help

Post by Snowmandopeman »

Thank you I appreciate the help, I will be getting started on it this weekend. I have the shop manual so that has been really helpful. just reading though and studying the shop manual has been really informative. here is a video of the issue
https://www.youtube.com/watch?v=HlnMmV1-QyY
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aj81spider
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Posts: 1526
Joined: Fri Mar 11, 2011 9:04 am
Your car is a: 1974 Fiat 124 Spider
Location: Chelmsford, MA

Re: DHSA2 Help

Post by aj81spider »

Not that I know anything, but have you tried setting the idle speed higher? From the video it looks like the choke keeps the car running at a faster idle and as soon as you push the choke in the car dies. Can you keep it running at a lower RPM by depressing the gas pedal a little? Try giving it some gas with the accelerator, then push the choke in and slowly let the accelerator out until it dies. If it dies at less than 850 RPM then it could be that the idle speed screw is set too low. If it still dies at 1100 RPM then that's not the problem
A.J.

1974 Fiat 124 Spider
2006 Corvette
1981 Spider 2000 (sold 2013 - never should have sold that car)
Snowmandopeman

Re: DHSA2 Help

Post by Snowmandopeman »

To be honest with you I have not and probably should give that a try, I just figured I would rebuild the carb and clean it first that way I am starting fresh.
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seabeelt
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Posts: 1614
Joined: Tue Feb 19, 2008 4:22 pm
Your car is a: Fiat Spider - 1971 BS1
Location: Tiverton, RI

Re: DHSA2 Help

Post by seabeelt »

Agree with AJ. Also the car is not warm per the temp gauge. Car needs to be fully warm - fan cycles on and off a couple of times before beginning adjustment. If its still cold it may need the choke to run.
r/
Michael and Deborah Williamson
1971 Spider -Tropie’ - w screaming IDFs
1971 Spider - Vesper -scrapped
1979 Spider - Seraphina - our son's car now sold
1972 Spider - Tortellini- our son's current
majicwrench

Re: DHSA2 Help

Post by majicwrench »

Fan does not have to cycle before engine will idle w/o choke. My 72 will idle just fine within a minute w/o choke in nice weather. Most typicly the idle jet plugs up o these carbs. Have you tried adjusting the idle mix?
Dougieb
Posts: 129
Joined: Wed Jun 16, 2010 6:37 am
Your car is a: 1972Spider

Re: DHSA2 Help

Post by Dougieb »

Hi,

When I ran my DHSA, I had to run the choke for a while until it warmed up a good bit.
I would progressively be able to let up on the choke until it was fully able to idle without it.
I would let it warm up well and then check the idle and mixture setting as per Artigue's guide.
You may check it against the factory setting or just check the "Final Setting":

4.9.1 Set Carburetor to Factory Settings
Back out the idle speed screw until it is no longer in contact with the throttle stop lever.
Now turn the screw until it contacts the lever and again 1 ½ turns.
Turn the idle mixture screw (on our carburetors it is typically in the center bottom of the
carburetor body) in until it is fully seated - do not force the screw. Now turn it back out
two full turns.

4.9.2 Start and warm the Engine
Disengage or block the choke open. On automatic chokes you can use a small clamp or
wire to pull the choke mechanism open. The engine should start and run poorly (if it
does not remain running then increase the idle speed screw ½ turn until it does). Adjust
the idle speed screw until the engine runs at approximately 900 RPM.
Let the engine warm up to operational temperature. On a Spider you will typically wait
until the fan has cycled two times (on-off-on-off). Turn the mixture screw in (lean the
mixture). If the engine increases in speed then continue to turn until it is no longer
increasing or runs worse, then back the screw out ½ turn. If the engine decreases in
speed then turn the screw out until it is increasing in speed. Continue to turn until it is
no longer increasing or runs worse, then turn the screw in ½ turn. Adjust the idle to
approximately 850 RPM.

4.9.3 Final Settings
Set the idle speed screw so that the engine runs at 850 RPM, or 900 RPM if you have air
conditioning. Recheck the mixture screw by turning slightly in then out. Engine speed
should be set - using the mixture screw ONLY - to the fastest and smoothest point of
operation (listen for exhaust popping). Reset the idle speed screw as necessary.
Drive the car under various loads (idle, cruise, hard acceleration, gradual acceleration,
etc.) for a short period of time then remove one of the spark plugs. The electrode should
be brownish-white in color. A white plug results from an engine that is too lean; a black
plug from one that is too rich. Adjust the mixture screw slightly to compensate.


I finally got my scanner to work.
Here is a break down of the carb.

Image

I left it intentionally large so you can "right click" and "save as" the photo.
Hope this helps.

Dougieb
Snowmandopeman

Re: DHSA2 Help

Post by Snowmandopeman »

Perfect I'll get on it tonight thank you for the help, the car temp gauge does not work all that we'll. in the video I had just gotten back from a drive. The issue that seems to be the biggest issue is the misfire that keeps happening. It miss fires at low rpm and high rpm. So I'll start with the carb and go from there.

Nick
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