Morning start-up general question

[stuartrubin]

Please understand that my '75 124 Spider is NOT optimally setup with regard to the carburetor, and I have some exhaust leaks. That said...

When I startup my car in the morning, it takes a few cranks to get it going, but always does start. Later in the day (maybe 5 hours later), the car has presumably cooled back down to outside temperature, it starts in the first crank. So what's going on here? I don't think it's temperature related since it has been resting for so long. It's not particularly cold in my garage in the summer. Battery is strong and the engine turns-over fine.

So, what's the difference between "resting" from 8 PM (done for the night) to 7 AM (drive to work, takes a few tries) versus 7 AM (get to work) and 12 PM (go to lunch, starts right up)?

What's settling, cooling, drying, humidifying, atrophying, etc. so differently for 11 hours in the garage versus 5 hours in the parking lot? The moon rays sucking the FIAT energy? The Cleveland sun putting it in a good mood?

Stuart

[jagonza]

i have an issue where when it is parked over night or longer, all the fuel drains back to the tank. I have installed check valves on the feed and return lines but it still happens. So when i go to start it takes a few cranks to get the fuel back up to the carb.

I installed a clear fuel filter and sure enough it does drain back every night.

this might be your issue.

[Nanonevol]

Could you do a clean and rebuild on the carb? If it's been a while that would be a worthwhile endeavor, improving your starting situation, idle and running. Not very difficult or expensive.

[PhillySpider]

Don't know if this'll help, but the owners manual for my 1980 states to fully depress the gas pedal to the floor 1x on cold start. I do it an she always fires right up!

[Dawgme85]

Check your fuel inlet and return barbs on the carburetor; that they are tight and not leaking air. On mine, you could watch the fuel leaking back to the tank, as indicated by bubbles forming in the (clear) fuel filter installed between the fuel pump and the carburetor. The barbs were loose enough on my 32ADFA that I could spin them and slide them in and out where they enter the carburetor. I once had the inlet barb completely disengage from the carb while driving (not fun, I can assure you). I thought that tapping them back into place would fix the problem, but after they came loose again I gave up and just replaced the top plate with a good spare that I had.

Since I replaced the carburetor top plate, the problem of hard starting when cold seems to have gone away. My local Fiat mechanic (Ray Mortensen) told me that SCCA used to make him install threaded hose barbs in the carbs of his Fiat race cars. I can see why...

Note that it could also be loose or leaky hoses anywhere in the fuel delivery system, so check those, as well.

[stuartrubin]

Thanks for the great replies!

PhillySpider (BTW, I lived in Center City Philly for many years...), the depress on cold starts is to engage the automatic (water heated) choke which I do. (If you go through my posts, you'll see that I've fought the choke and other carb problems for a long time!) Still, great suggestion for other newbies who might not know about it.

Nanonevol, the carb is still pretty new. I installed it towards the end of last summer and didn't use it until a month ago or so. It's possible that it's gummed up, or messed up, but better not need a rebuild after only a hundred miles or so!

I'll check for air leaks and back flow. Not sure how to diagnose it if I don't see anything obvious like the bubbles, but maybe I'll get lucky.

Stuart

[GeorgeT]

If you still have the dual point distributor you might start there and make sure it is trying to start on the retarded set of points rather than the advanced set.

[dreavis]

My 77 has the same issue, but I assumed it was symptomatic of being almost 40 years old. I guess I should look into it.

[Dawgme85]

After 40 years, the rubber hoses are prone to hardening and cracking, so you're on the right track, dreavis. Mine had been replaced within the past few years, so are in good shape. Just look for hard hoses that can't be clamped tight to the steel lines, or are split.

Regarding the bubbling that I saw, I just happened to have the hood open while showing off my new starter (warm engine) to Ray and happened to notice an occasional bubble appearing in the fuel filter as we were talking and thought "aha!". He offered to modify my carb to add the threaded barbs, but I had a spare carb which, fortunately, had tight barbs, so I just did the swap myself. As it turns out, the next time I saw him he had modified a top plate, which he probably still has. Google "Performance Apex" if that turns out to be your problem and you need one. I see the op has a new carb...

Good luck.