Question
1971 Merceds Benz 250C
I have had a 1971 250C restored. The Zenith carbs were rebuilt @ 1,000 miles ago.
The car cold starts fine, runs on the road like my old 944 Turbo, but after sitting awhile when hot, it is almost impossible to restart. It stumbles along on a few cylinders, the carbs make a "whoosh" sound(not a backfire) and it just idles back down and stops. Horrid gas smell when this happens. Sometime, I have to wait over an hour before it will restart. And, even then it involves cranking and cranking the engine.
What do you believe may be the problem, and the solution as, except for this issue, this is a great car.
The car is also only getting a very carefully documented 12.71 MPG.
This issue seems to be beyond the shop that re-built the car as after $500, they don't seem to be able to fix the problem.
Answerfirst question I have to ask is who rebuilt the carbs and what parts were refurbished, and once back on the engine, were they tuned? Sure sounds like a flooding issue, so your choke is stuck or you have a vacuum leak.
The elusive adjustment for that is usually the vacuum pull-off of the choke plate which engages too little and floods the engine Zeniths once adjusted properly should allow swiss clock like running cold or hot
Tunning Zeniths is best left to a pro, preferably an old MB mechanic.
Check out this link from a cyber buddy of mine
http://www.jaimekop.com/CarbManual/Page24-25/index.html
and here is the whole manual ( click on carb link)
http://www.jaimekop.com/
good luck, let me know if this helps
Ron
