Question when replacing an automotive carb with a Marine Holley 650

gwizzar

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It was suggested to me that “When you rig your fuel system and carburetor keep your eyes open for the clear vent tube that runs from the fuel pump to the carburetor. It is a tell-tale for you to know if the fuel pump is running on its original diaphragm. If it ever fills with fuel you then need to replace the fuel pump. That is how it tells you the pump has worn or broken the main diaphragm and that it's on the backup diaphragm. Yours is new so it won't likely fail for many years if at all.
I bring it up since your car engine would not have had that part, plus your marine carburetor should have a hose barb on it for the clear line. I'd expect the engine to run poorly if that vent isn't occupied correctly. Plus you want the fuel system completely enclosed to minimize vapors in the bilge area.” The Holley Performance 650 CFM Four Barrel Carburetor did not come with a clear line... What do you recommend in regards to a clear fuel line and should I use hose clamps or something else?650 CFM Four Barrel Carburetor.jpgclear line.jpgFigure 1 illustration.JPGhose barb.jpginlet is for "Fresh Air." Am I reading it wrong? Please refer to pics. Thx!
 

achris

More fish than mountain goat
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Re: Question when replacing an automotive carb with a Marine Holley 650

Hey,

My suggestion would be to return that holley to whence it came, and get a Edelbrock 1409 (http://www.summitracing.com/parts/EDL-1409/).... MUCH better.. and it has a port for the fuel pump safety line...

In brief, that clear hose from the fuel pump is on the underside of the pump diaphram. If the diaphram leaks, instead of the fuel pouring into the bilge (with the resultant "BOOM") it runs up the tube and pours into the carbie, flooding the engine to a stop and making you check things out.... Simple as that.

The carbie won't come with the clear hose, that's something else you need to get, but the carbie does need a port for the hose to connect to (usually just a barb, about 1/4")...

Chris......
 

gwizzar

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Re: Question when replacing an automotive carb with a Marine Holley 650

clear line.jpghose barb.jpg
Hey,

My suggestion would be to return that holley to whence it came, and get a Edlebrock 1409 (http://www.summitracing.com/parts/EDL-1409/).... MUCH better.. and it has a port for the fuel pump safety line...

In brief, that clear hose from the fuel pump is on the underside of the pump diaphram. If the diaphram leaks, instead of the fuel pouring into the bilge (with the resultant "BOOM") it runs up the tube and pours into the carbie, flooding the engine to a stop and making you check things out.... Simple as that.

The carbie won't come with the clear hose, that's something else you need to get, but the carbie does need a port for the hose to connect to (usually just a barb, about 1/4")...

Chris......

It has the port, Chris. plz see image. I just need to know the type of clear line/hose to use and how to secure the hose/line to the port.hose barb.jpg
 

achris

More fish than mountain goat
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Re: Question when replacing an automotive carb with a Marine Holley 650

Any clear/translucent fuel resistant tube of the right size... The hose should be the right size to push on securely, there's no pressure in the hose... Use a cable tie if you must...

Chris........
 

gwizzar

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Re: Question when replacing an automotive carb with a Marine Holley 650

Any clear/translucent fuel resistant tube of the right size... The hose should be the right size to push on securely, there's no pressure in the hose... Use a cable tie if you must...

Chris........

Golden!
 

Bondo

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Re: Question when replacing an automotive carb with a Marine Holley 650

Question when replacing an automotive carb with a Marine Holley 650

Ayuh,.... The Holey was Never used by Mercruiser,....

Volvo used a few....

The Edlebrock is a carbon copy of the Merc carb...
 

achris

More fish than mountain goat
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Re: Question when replacing an automotive carb with a Marine Holley 650


What I would use is a product called 'Tygon'..

And I still say change that horrible holley to a nice Edelbrock... :D
 

gwizzar

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Re: Question when replacing an automotive carb with a Marine Holley 650

What I would use is a product called 'Tygon'..

And I still say change that horrible holley to a nice Edelbrock... :D

Lol...Don't care for Holley much?
 

vndkshn

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Re: Question when replacing an automotive carb with a Marine Holley 650

I much prefer a Holley... If I don't go FI, eventually I'll put a Holley on mine.

And I'd say the Merc carb is a "carbon copy" of the Edelbrock/Rochester carb... not the other way around!
 

Bondo

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Re: Question when replacing an automotive carb with a Marine Holley 650

I much prefer a Holley... If I don't go FI, eventually I'll put a Holley on mine.

And I'd say the Merc carb is a "carbon copy" of the Edelbrock/Rochester carb... not the other way around!

Ayuh,.... Merc quit usin' the Rochesters Decades ago,...

The Merc/ Weber, 'n the Edlebrock's We're talkin' 'bout are actually up-dated versions of the Carter, AFB carbs...

I believe Edlebrock also does something with the obsolete Rochester spread-bore's too...

The fore, 'n aft fuel bowls on the Holleys are also less conducive to the angles encountered in a boat...
 

Don S

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Re: Question when replacing an automotive carb with a Marine Holley 650

I'm not a Holly fan at all. But Volvo used Holly carbs for a lot of years with no problem.

On that clear hose, any hardware store pvc clear hose will work fine. It will never have anything in it but air unless the pump fails, if that happens you can see it in the hose and the pump needs replaced. The gas will not immediately destroy the hose. I use that cheap clear hose on test gauges and pumps all the time with gas in them. No reason to go with expensive special made clear hose for that job.
 
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