Re: Henry's 37 Limousine

Posted by Owen_Dyneto On 2017/4/10 15:23:10

Howard, it seems to me that its going to pretty difficult if not impossible for liquid fuel to leak from the throttle shaft or a crack in that vicinity when the engine is running. I don't see how the fuel will be able to exit against the air flow being drawn in by the manifold vacuum. To my way of thinking, leakage is going to occur when the engine has been shut down and fuel is being forced out the jets and down the venturi due to a leaking needle and seat and/or a float level set too high, or similar.

I believe the major reason carb shops bush and reshaft throttle assemblies is that the vacuum leak translates into a lean mixture, just as would happen with a leaking intake manifold gasket. That is, air has been drawn into the combustion chamber which HAS NOT passed thru the venturi and hence contains no fuel vapor.