1929 Auburn Schebler Carb

I have a 1931 898A, also Schebler updraft carb, and the instruction for using the heat valve is the same. I've wondered about this, and speculate the following. Fuel in the 20s and early 30s was less volatile, so heating it was a way to make the cars run better when they were cold (always push it back in when the engine warms up, of course). We may be driving cars of the 20s and 30s, but we aren't using fuel from then, in fact our problem now is more likely to be vapor lock than fuel that does not want to combust. Thus, the heat valve may be a relic, a solution to a problem that no longer exists. I don't notice that it does much, so possibly consistent with my speculation, tho not proof for it. Anyone else have thoughts on this? We still need choke and spark retard, but possibly we can now ignore the heat control.
Jack Triplett

not 8-90 though should be similar

Thanks! what can you tell me about the manifold heater?

Sounds to me like a contamination problem, The Dyke's carburetor supplement is a good guide, the Gardener car link should help. www.gardnermotorcars.com/tech/MoToR%20Handbook/Schebler.pdf
I have found the Schebler type "S" to be a very reliable and simple carburetor. It is an air valve type carburetor with a fuel filled dash pot and no choke butterfly. The fuel is enriched by lifting the needle for cold starts. Sticking of the air valve, bad alignment of the air valve and water/contamination are the main problems if it is a fuel problem. I have found it is necessary to have a good inline fuel filter.

Also, when driving should the manifold heat cable be in the on or off position?

thanks

Hello,

we have a 29 8-90 it ran great let it sit for about a month now runs rough back fires and will not run unless the choke is pulled partially out. I want to drain the gas and drain carb. there appears to be a plug on the bottom of the carb. What else should I look for? Also in the pic of the carb. What under the plate on top?

Thanksin advance.