carb issues

[fiatrouge]

My wife just recently aquired a Fiat 124 Spider 1974 - seems to be a fairly solid little vehicle - BUT I have a few questions for the Fiat minded. The guy we bought it from said the gauges were all in some other language, he thought perhaps it was French. Needless to say - he didn't know anything about it. He was driving around with low antifreeze due to a nasty leak under the dash, I bypassed the heater core until I can investigate if its the valve or the seal on the valve.

Her car does shift well, however runs strangely very tenuous after that. It seems to need to be warmed up just perfect, and shift gears, just perfect, or you get the herky jerk action. *bucking bronco*. The car runs rich it seems blows a little smoke when shifting gears and smells gassy. Then I think the rich fuel conditions cause a plug to foul a little and its undriveable, it will run, but its the ride of your life. With or without a load on the system it sputters and misses on and off for a few seconds, then will drive again "normally" again. At first I thought I was running out of gas on the uphill but I filled the tank and got more of the same. Its almost like a muffled backfire - out the exhaust. You have to ride the "envelope" if you lift off or hit the gas, you get the bronco again.

ORRR

is it a vacuum leak causing a rich condition - one of the vacuum do dads not doing its thing. If anyone has a link to the right solution to this problem, I would be interested.

The car very seldom will run REALLY NICE which leads me to believe that I could have that all of the time!? Normally I am a VW person and have a Mk1 (cabriolet) that I am driving. So I am somewhat used to high revving small motor cars. Sorry about the long winded questions / intro = any suggestions would be appreciated.

[So Cal Mark]

it could just be a carb problem, but I'd start with the basics and check cam timing first, then dwell and timing before going into the carb.

[fiatrouge]

Today we changed the plugs - it seems to be better - at least its not missing. Still have the rich running condition and the chug a lug. I found a vacuum fitting on the carb, and another on a do-dad on the fenderwall, so I put a hose between them. I don't know if it was right, but they both looked like they were missing something. I think I have a fuel problem - the mix - which brings me back to vacuum leak. I think under a load the vacuum increases, and the leak leaks more, and the engine bogs more. Then after pulling over, things settle out, and we can drive away again. Tomorrow I will look more,,,,,ANY suggestions or similar experiences?

[So Cal Mark]

vacuum drops under load. What did the plugs look like? Sooty? Wet? I'd still start with the basics before going into the carb. But definitely check the carb mounting bolts for tightness

[fiatrouge]

Seems - I am embarrassed to say - it is a carb issue- I put a new fuel filter on - the old one was plugged pretty good. BUT thats not it, we were messing around with it and looking down the carb. Seems one barrel gets gas, and the other doesn't. SO we have been driving around with a one barrel. I think a carb rebuild is in order. The history of this car is a little unknown, a deputy who bought it off a "mechanic", who got it on a mechanics lean. Pretty low miles. But during all the hand offs, I think it may have had the same 7 gallons of gas in it. The carb rocks very very slightly. but the gasket seems firm and sealed. So we are going for the carb rebuild at this point. The plugs looked dry, a little blackened, with a strange white/grey haze. Not gassy - as I would have expected. When following behind the car (in another convertible), at shifts it puts out a puff of black smoke, and smells gassy all the time.

I guess I still don't understand, the vacuum thing, the faster the motor turns the more vacuum, so at load the vacuum goes down.

Another question....My Haynes manual says if you need to replace a temp sensor for the "water" gauge to go to an authorized fiat mechanic. I thought if I had bought the book I was authorized. Can anyone tell me where this sensor is located? I don't want to start pulling sensors randomly to look at them. It rides along at 180 and then suddenly pegs the top - then after a few restarts or a big bump drops back to normal again.

THANKS So Cal Mark! for the input on this matter, I think you're first instinct is correct - carb issue.

[So Cal Mark]

your carb is progressive; the secondary venturi will only have fuel flow when the secondary throttle plate opens. The carb shouldn't rock at all. If the mounting bolts aren't loose, then the carb body may be loose
The temp senders are in the middle of the cyl head, between the spark plugs.
BTW, an authorized Fiat mechanic is one that the Fiat factory has authorized to do repairs. That means repairs that are performed according to mfr specs and they have knowledge of the cars, not just posession of a book

[fiatrouge]

I squirt the heck out of the carb throttling up and now no herky jerk - its nice and smooth - although I am missing on one cylinder again. AND I found a secret fuel filter in the trunk - there was another under the hood. So now I have replaced them both and see improvement. I think the pump may not be up to par - I put clear filters on, and they don't really fill up with gas. The one in the trunk - gets about 1/2 full and the one under the hood maybe gets 1/6th full. Pump does make noise with the key on and you can see movement in the filter. But is it enough? When cruising today we could get to highway speeds - and climb hills without bouncing, But we would loose speed on the hills - which at this point I am going to attribute to missing on one cylinder. Makes for a sputter up to 30 - 40 mph then seems to spin fast enough to smooth out the sound - at first I thought it was only missing at low rpms.

again - thanks for your input - it has been very helpful plans for tomorrow include, Locating new cap and rotor. (already changed plugs and wires and air filter) Changing water sensor for gauge. Put the timing light on the plugs wires to see that everybody is firing still. The front plug seems to have been slightly stripped or cross threaded. You have to VERY careful to get it started right - or it binds up. You can see the top few threads are a little stripped looking. SO I suspect that one - because it will be the biggest pain to fix if its a problem .

The distributor as I mentioned I belive is also in "backwards" the first two and the last two are 1/2 rotation off if you catch my drift. So I am going to see about pulling it and turning it around, or whatever I need to do to get them in the right places. They are in the right order however. That couldn't mess anything up - I wouldn't think as long as they are in the right order?

anyhow thanks again - I have a lot to think about. I think I will really like this car if I can get it lit right.

mike

[So Cal Mark]

the filters won't fill completely