850 Spider stalling and difficult to restart

[hairgoneJohn]

Hi


I've recently purchased a 1973 Fiat 850 Spider and when hot the engine hesitates and frequently stalls and is difficult to restart. I've noticed that the distributor is getting too hot to touch. There are no heat shields to protect it from the exhaust manifold heat. Is this normal?
The ignition has been converted to an electronic pickup and I'm wondering if it might be failing due to the heat. Do you think that this is likely and is there a test to check. I read somewhere about putting a bulb across the coil terminals to check. Sadly my electrical knowledge is lacking.


I originally thought that the problem might be fuel vaporisation but I've routed the pipes and electric pump to the front of the firewall and it has made no difference.


Any tips on diagnosing the problem would be appreciated.


Thanks
John

 

[ppalma]

I've had something like that happening on my 850 Coupé. I had an air leak between the carburetor and the manifold, and it got worse when the engine was hot.
I traced the problem to the threaded studs that hold the carburetor to the manifold. They had been overtightened and stripped the threads from the aluminium casting.
It seems to be a common issue, as I have three Weber 30 DIC, and all have their threads stripped.
To repair either get some threaded inserts, or longer bolts and nuts.
P.S. To properly diagnose this leak, spray a flamable liquid or gas to the suspected area. If the engine revs up, you've got a leak.