Re: vacume tank or vapor lock 1929 626

Posted by DavidM On 2012/9/1 17:25:28

This sounds like classic vapor lock, a subject that has been discussed many times before on this and the AACA forum.
In warm weather I need to leave the hood open on my 633 if the car is to be restarted in a short time otherwise under hood heat vaporises the fuel making the car hard to start.
Fitting a shroud around the vacuum tank to shield it from radiant heat from the exhaust manifold reduces vapor lock on these cars. This works best if it is made from polished stainless steel.
I find that adding kerosene to the fuel helps, others have reported that diesel has the same benefit.
I wonder whether the fuel filter you have fitted is restricting the fuel flow given that there is a very low pressure by gravity feed from the vacuum tank to the filter, this might be adding to the problem. I rely entirely on the sediment bowl for filtration and have never had a fuel blockage issue in over 20 years.