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Carb Sight Tube

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slickcrafthbc

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Does anyone know the purpose o

Does anyone know the purpose of the small clear tube that connets to the carburater refered to sometimes as the sight tube?
 
"Jeff, That is a fuel recover

"Jeff, That is a fuel recovery tube. The purpose of the tube is to protect you from dumping raw fuel in your bilge in the event of a fuel pump failure.

Normally when a mechanical fuel pump fails, in your car, it dumps fuel either in the crankcase or on the ground. In the case of a marine type pump this fuel is returned, via the tube, to the carb where it is safe to discharge.

This is one of the reasons it is so important to use only marine components on your marine engine.

Rick"
 
"Jeff: If it is connected on

"Jeff: If it is connected on the other end to the fuel pump, it is there to let you know when one of the fuel pump diaphrams is leaking in a two chamber pump. When your engine runs rough and you see fuel in the tube; change the pump.

However, on an old pump, the outlet port on the pump to the tube can become plugged with varnish from a small leak and not give the telltale sign of a leaking pump. I chaged my 19 year old pump last summer due to its age and that is exactly what I found. It was plugged like cement and the chamber was full of crap when I disassembled it.
Guy"
 
"Jeff
If you look at USCG reg

"Jeff
If you look at USCG regs, this line is required on a carb to take fuel back to the pump if the float sticks. This keeps fuel out of the blige in the old days carbs floats stuck sometimes. Also if you replace fuel line (gas) USCG requiers double wall gas line. Unlike cars which use single wall line."
 
".."If you look at USCG re

".."If you look at USCG regs, this line is required on a carb to take fuel back to the pump if the float sticks. "

I believe this is true ONLY of boats built after a certain date. My 1985 cruiser, for example, did not have the third line. That said, I added them to both engines, just to be safe.

JEff"
 
""If you look at USCG regs

""If you look at USCG regs, this line is required on a carb to take fuel back to the pump if the float sticks. This keeps fuel out of the blige in the old days carbs floats stuck sometimes. Also if you replace fuel line (gas) USCG requiers double wall gas line. Unlike cars which use single wall line."

Huh,........

Just What are you talking about.......
Rick's got it Right........
Marine Carbs are Vented into the Venturi to take care of Stuck Needle Valves......
Not back to the Fuel Pump......

And,....
The CG Doesn't Require Double Wall fuel lines,.....
Just Fuel Lines that are Certified by the CG.....
Google up the Regs,+ you'll See......."
 
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