Marvel carb failure, water in the accelerator well

A collection of technical articles & attached documents by Neal Wright
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Name: Neal Wright
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Marvel carb failure, water in the accelerator well

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Originally Posted on Sat Nov 19, 2005 10:07 am

This article shows the hard way to find out that your Marvel carburetor can allow water into the accelerator well and induce corrosion.

There are two types of castings and each has a different method of sealing the opening into the accelerator well; if the older variety develops a wear leak around the seal, bad things happen.

This has pictures of the accelerator pump system, indicates how it works, and shows the results on two occasions when water from engine washing entered the worn seal around the pump shaft. The water has no escape path so it stays and corrodes, eventually leading to, in these two occasions, the failure of the pump to pump and to prevent the throttle from moving beyond half open.

There is a companion article about how the mixture control works and how to make sure it is achieving full movement.

An alert as to the damage that can be done if water gets into the accelerator pump.
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