850 Sport 30 DIC Carb

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850 Sport 30 DIC Carb

FH3543

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What? no 850 specific section in the Forums?

Recently bought a 1970 850 Sport. Motor has apparently been reconditioned and not really driven since. Got her home and she was running a bit rough.

Fuel pump had a small leak, so I opened it up and noticed the pump filter was clogged with rust. So, took the carbie (30 DIC 23/23) apart and found it full of rust. Did I mention there wasn't an inline fuel filter installed? Sigh.

Tank obviously has gone rusty while sitting around.

Ran well after carb clean, but despite installing inline filter, there was obviously some rust still in the system and the jets clogged. Cleaned a couple of times and ran, but decided I'd flush all the lines and reclean the carbie.

But it all back together and now it doesn't want to start. Spark and timing have been checked. Not sure what I did wrong. It just cranks forever without firing. Couple of times it fired and ran for a second or two, but dies almost immediately. Can't get revs up. Tried a bit of ether (a can of "Start Ya' Bastard"!), but apart from a small fire or two, nothing.

Knowing enough to get myself in trouble but not enough to necessarily get out of trouble I'm a little stumped. I just studied a diagram of the carb and noticed that there is one part of the carb that I didn't specifically clean - the emulsion jets. I unscrewed the bung above them, and probably squirted cleaner down the holes, but didn't remove then and clean them. Didn't know I could.

So, is it possible that the emulsion jets are my problem? Have I possibly flushed all the rust into the emulsion jets and clogged them while cleaning?

How do I get them out? Do I need to use pliers or something?

Sorry for all the questions! Just hoping for a little advice before I pull the carb off again.

No, I didn't change the gaskets in the carb or on the manifold. Will do in future, but they seemed to be in good shape...

Finally, I've seen reference on mrFiat to a fuel pressure regulator for the 850 - I don't have one. Is this necessary when running the standard mechanical fuel pump?

Sorry again for a long post full of questions!
 
It's unlikely that the emulsion tubes are to blame.
I own an 850 Sport Coupé and have rebuilt a couple of 30 DICs. There's nothing much about them.
Are you getting any fuel inside the cylinders? Try resetting the carb's mixture screw. Is the choke working?
I also don't run an inline filter and it's ok, the pump's and the carburetors' filters are enough. A pressure regulator is not required for a mechanical pump.
 
Hi FH3453

The starting problem sounds more likely to be the condenser on the distribibutor, they generally fail after not being used for ages, especially if the ignition is switched on for long periods with the engine not running.

it will cost a couple of £s for a new one but dont change the points gap.

have fun

Tim
 
Hi Guys

Thanks for the responses. Sorry for the delay in getting back, been on summer holidays here in New Zealand.

Tim - you were right, I've put it back together and replaced the condensor and shes running very well now. Thanks very much!
 
Hi!
Can someone of you be so kind and post some pictures from the 30 DIC, and its mount on the manifold? I plan some changes on my Marbella (903ccm, 09NCB engine) and I plan to change carb too. One option could be a 30 DIC. :)
 
I am currently driving a 1971 850 Sport Spider. ( Sold my "72 850...)

If your carb is full of rust then I suggest that you rebuild it. The rebuild is a small price to pay for the piece of mind that it is clean.

A rusty fuel tank needs to be removed, treated, and replaced before putting gasoline back into it. (KBS, Eastwood, Red Coat, etc... all sell good DYI kits).

I would not run any motor without an in-line fuel filter. Again, a small price to pay for a clean system fuel system in the carb and motor.

If "emulsion jets" are the idle jets or the main jets on your carb, then by all means they need to be inspected for blockages. The jets can be removed with a flat blade screw driver, thoroughly cleaned, and reinserted into their respective places.

As far as a fuel regulator goes, you do not need one if you are running a stock mechanical fuel pump. If you are running an electric fuel pump (which I would recommend), then get a 4 /6 pound electric pump, and you will not need a regulator for that as well. Just block off the mechanic fuel pump opening (a number of distributors sell a plate that fits well and seals this opening) and install the electric pump on the left inside fender by the windshield wiper fluid bag.

I hope that this helps out. I have done a number of upgrades to my 850's to make them more reliable, and am happy to share... v:D

It is good to see questions about the little rear engine car that can....

850 Dave
 
Hi All,
I have just found and joined this amazing looking Fiat Forum. New to the site, so not sure if i'm in the right area of the site to post this?
I have a 1970 Fiat 850 Sport Coupe that I have had for four years in storage, and am finally stating the restoration work on it.
Just wanted to say hello!
Cheers,
Phil.
 
HI Phil.

Welcome. Any more Description or history, colour info etc.

Tim
Hi Tim,
Thanks for your response and welcoming! Apologies about the late response.
The car was purchased new in Adelaide SA and owned and used (and garaged) for 37 years by a little old couple who eventually sold it to their nephew. He intended to restore it but found he didn't have the time and sold it to a Mopar engine restoration bloke a few months later. The Mopar guy sold it to me pretty much soon after he'd bought it (this was in 2017).
The car is an off-white colour, is very straight with virtually no rust which was a big draw card for me! I have purchased new steering, brake, suspension and engine mount parts from Ra Auto in Switzerland, a 123 electronic distributor from 123 in the Netherlands, a NOS abarth exhaust unit among other parts from around the globe - All yet to install.
Currently I am having trouble with what appears to be an accelerator pump problem in the Weber 30 DIC. I have rebuilt the carb (stripped, ultrasonically cleaned, fully blown out with air and reassembled with a full new kit. The ball valve appears to be operating between the pressed brass pin and the seat in which it sits - although I couldn't pull this apart. Fuel squirts out the beak nozzle into the primary venturi when the lever actuates the diaphragm from the cam on the throttle shaft, but I have no means of measuring this/ metering this to see if it is the correct amount injected?
The engine starts and idles nicely (have adjusted the mixture screw & throttle stop screws) and it will accelerate gently all the way up to maximum revs - but sharp acceleration from idle sees it gulp, cough and backfire through the carb? Timing is correct at 10 degrees BTDC.
All other componentry is new - condenser, points (set correctly) rotor, cap, ignition leads and plugs. Have swapped out both the coil and condenser again to eliminate them. The petrol pump is new and I have a new in-line filter which is running clear.
I think the 98 0ctane fuel that is in it is pretty old (filled the tank up not long after I got it so as to prevent corrosion). New fuels these days don't last long I'm told so will drain and refuel with 95 as I think it's closer to the old leaded fuel.
Anyhow, enough of my ranting!
If anyone has some sage advice/ wisdom on this conundrum of mine, I would be grateful to hear from you.
Thanks again Tim for your contact!
Cheers,
Phil.
 
Currently I am having trouble with what appears to be an accelerator pump problem in the Weber 30 DIC. I have rebuilt the carb (stripped, ultrasonically cleaned, fully blown out with air and reassembled with a full new kit. The ball valve appears to be operating between the pressed brass pin and the seat in which it sits - although I couldn't pull this apart. Fuel squirts out the beak nozzle into the primary venturi when the lever actuates the diaphragm from the cam on the throttle shaft, but I have no means of measuring this/ metering this to see if it is the correct amount injected?
The engine starts and idles nicely (have adjusted the mixture screw & throttle stop screws) and it will accelerate gently all the way up to maximum revs - but sharp acceleration from idle sees it gulp, cough and backfire through the carb? Timing is correct at 10 degrees BTDC.
This is a delayed response, and I'm hoping you've made progress, since it's summer in your part of the world.

From the description, it doesn't sound like the problem is your accelerator pump. If it squirts when the throttle is opened rapidly and it's not visibly blocked, then it's operating as it should. (Metering for the pump is completely based on the diameter of the opening.)

When I've had problems like this, it was because another carburetor jet was blocked somewhere, the timing was off, and/or there was an air leak at the base of the carb. My suggestions (based experiencing lots of problems like this on an 850SC and a 600D and lots of helpful advice from other forums like this):
  1. First try manually adjusting the timing a little bit to see if that helps. Exactly 10 degrees BTDC may not be exactly right for a 50+ year old car.
  2. Second test for leaks at the base of the carburetor. Do this by spraying starter fluid or carb cleaner at the base when idling. If that causes the revs to increase you have a leak. (You need a gasket above the drip pan and another below. Make sure they are both present and good.) Apparently these leaks are quite common and are caused by warping of the carb base over time.
  3. Third, back to timing...Open the distributor and check the weights that control manual advance. If the weights are stuck or the springs have weakened then the timing will be messed up at higher revs.
  4. Re-open the carb and look for blocked jets or other sources of potential air leaks, like where the throttle spindle enters the carb body.
If you don't have the Haynes manual, I highly recommend it.
 
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