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Frustrating Day with HS6 carbs

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rick_ingram

rick_ingram

Yoda
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Today did not go nearly as well as yesterday.

Worked on the 68 MGC. No fuel is getting past the float bowls.

Traced the supply of fuel from the tank all the way to the carbs.

Fuel will deliver all the way to the bowls.

After the bowls fill, there appears to be a lock of some sort happen...where fuel is no longer supplied to the carbs...I have a clear filter in the engine compartment and can watch the delivery trickle down to nothing. This happened with one SU fuel pump and two electronic pumps, each delivering #2 - #3.5 psi.

When I pull the feed lines to the bowls, fuel delivery is normal....into a pan.

The car would start when I tried spraying some starting fluid not only into the neck of the stock air filter, but directly into the carbs themselves.

I opened each bowl...neither was overly dirty.

Can the needle of each carb be varnished or blocked such that this will cause the delivery of fuel to completely stop....

No fuel is forced from the vent tubes of either carb.

Thanks in advance...

rick
 
How fresh is the fuel?
 
About 3 gallons of fuel purchased ths month and added to about 3 gallons of last season fuel, treated with Stabil.
 
[ QUOTE ]
About 3 gallons of fuel purchased ths month and added to about 3 gallons of last season fuel, treated with Stabil.

[/ QUOTE ]

Ok, scratch that. Are the floats doing their thing?
 
I emptied the floats bowls and cleaned them out. They both refilled immediately upon the next attempt. Both floats pivotted easily..and appeared to be intact.
 
But are the float valves stuck closed, pull em out and clean well and slip em back in. Make sure they drop when you move the float up and down.
 
is the line that connects the float bowls to the jets clogged?

are the jets gummed up?

How's the action of the vacuum pistons?

uhm.... is the choke working like it should?

Keep in mind SU carbs are demand only type carbs. So, fuel will NOT spray into the system when you mash the accelorater with the engine not running. If you're not getting ANY fuel into your intake, and the float bowls are filling up. I'd look at the jetting and the vacuum piston (in the dashpot). Make sure the piston isn't stuck, moves freely, smoothly, has oil in the damper tube, and the proper return spring is installed.

Hope this helps.
 
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