Penta 3.0 ('97 Four Winns) air/fuel adjustment -- where is the vacuum port?

soundquest

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Aug 1, 2019
Messages
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I am attempting to adjust the air/fuel mixture (2bbl Holley Carb on a Volvo 3.0 -- 1997 Four Winns Horizon) and need to know where the vacuum port is on the intake manifold. Thank you.
 

Bondo

Moderator
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Apr 17, 2002
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Ayuh,..... Welcome Aboard,..... Boat motors rarely have a vacuum port,.....
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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18,134
Your best bet, get a FACTORY service manual.
The Clymer and Seloc are ok but nothing like the factory book.
 

kenny nunez

Captain
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Jun 20, 2017
Messages
3,430
If the engine does not stabilize with the metering screws 1.5 give or take 1/4 either way either the carburetor needs rebuilding or something else is wrong with the engine. There should be a pipe thread plug on the top of the manifold that can be removed and replaced with a hose barb fitting.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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51,141
use an un-lit propane torch and your tach when adjusting AFR
 
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