Sunbeam Alpine: Overcoming Hot Starting Problems

This video shows how we have made minor modifications to our Alpines to prevent problems we experienced when re-starting the cars while they were hot. We believe that modern petrol vaporises much more readily than the fuel of the 1960s and 1970s did and causes a lot of the hot start difficulties that many classic car owners often suffer from. Taking steps to keep the fuel feed cooler and to ensure that there is always petrol at the carburettor very efficiently removes the problem for minimal cost and effort. Since we did this we have had no more problems.

[@brianhaw9398]

This brings back memories. I had a '64 series4 gt. My buddy had a '67 series 5. I think they al had this issue.

[@TheSunbeamAlpineChannel]

Brian, I think you are right! Lots of the old classics suffer from this now with modern fuel but it can be overcome with a bit of re-plumbing..

[@stagweberVMad]

Problems with hot starting are usually too rich a mixture. When the fuel gets hot and vapourises, the increased pressure overcomes the float valve and lets fuel into the inlet manifold. This richens the mixture which makes it difficult to start. As proof, try pressing accelerator slowly to the floor and let the excess vapours evaporate. Then crank the engine and the extra air will purge the fuel vapour allowing the engine to start.

[@TheSunbeamAlpineChannel]

That has certainly worked for us on occasions.

[@caffjohn]

More so with downdraught carburettors than sidedraught in my experience, the dreaded ford VV was notorious for doing it.

[@TheSunbeamAlpineChannel]

@@caffjohn It is a shame that petrol has changed so much that we get these problems now. Every hot day we seem to see a classic car having fuel problems.

[@peterthomson5403]

I am not a fan of putting an electric pump before the mech pump ,if the diaphragm in the mech pump gets a small hole the electric pump will dilute the sump oil , which can cause bearing failure or a big bang .

[@TheSunbeamAlpineChannel]

We agree with you Peter running the two pumps in series is probably asking for trouble. In the video the white car has an electric pump only and the red one has a mechanical pump only. Some people install an electric pump and have both but with alternative piping so that an electric pump can be turned on just at certain times (such as when stuck in traffic on a very hot day). That seems like a reasonable solution but we have not done that..