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Old 01-16-2020, 10:30 AM   #12
Merc Cruzer
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Join Date: Jul 2010
Location: Conifer, Colorado
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Default Re: Bench testing the economizer diaphragm on a Holley 1901 (teapot) carb

Quote:
Originally Posted by scicala View Post
To test it properly need to clean any dirt and make sure it's dry around the center hole for the air cleaner stud. Then seal both sides of the hole with a small piece of masking tape. I say this because the vacuum channel to the diaphragm passes through this area and is sealed by a brass bushing. The bushing sometimes doesn't seal well. This is why it's important to snug down the air cleaner stud to seal it once assembled again.
You can use your mouth to apply vacuum to the hole in the cover, then see if the diaphragm collapses and stays there. If any leaks (besides a bad diaphragm), it's usually because the diaphragm is pinched. Best to install it with the spring partly collapsed, as to keep the diaphragm flat when tightening the screws.


Sal
The kits I have bought recently have contained these washers, that I have been using them to seal the top of the carb. The tops without the brass bushings seam to seal better.
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Last edited by Merc Cruzer; 01-16-2020 at 11:10 AM.
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