Visit our Twitter feed for more great content
AHExp

The 100-Six Forum

Fuel issue

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

Texas57 Silver Member Robert C
Stephenville, TX, USA   USA
In my 57 100-6 I have an issue with the fuel running out of the carbs/ fuel filter and back into the tank. It makes for a long refilling of the filter and carbs before starting most times. Any suggestions? Should the SU fuel pump not allow the fuel to be siphoned back into the tank or is there a faulty or missing one way valve?

Thanks

Robert

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
Robert,
A leaky internal valve in the pump is exactly what it sounds like. I believe that some fuel will drain back that is why when you turn on the ignition the fuel pump runs for a few seconds then stops. It is refilling the lines and building up the necessary fuel pressure.
Pete

Randy Forbes Avatar
Parrish, FL, USA   USA
1957 Austin-Healey 100-Six
1999 BMW M Coupe "Blue Car"
1999 BMW M Roadster "Black Car"
2001 BMW M Roadster "Gray Car"
It's pretty normal for the carb float bowls to require refilling, as heat in the engine and compartment causes quick evaporation when it is shut off, as a result of heat soaking back to the carbs. Even when just stopping for lunch and restarting the car an hour or so later, it can take 10-20 seconds of (rapidly ticking) fuel pump running before it settles down.

If the car is parked overnight, or from one weekend to the next (or a month to the next time it's started up) it can easily take 20-30 seconds to fill the bowls and charge the lines. My modus operandi is to switch on the key as soon as I get in the car, then put on my seat belt, check mirrors, seat setting, etc., and once I've done that, she's ready to be started up.

Please note that my estimates are based on the time it takes with a Facet (interrupter/cylindrical style) fuel pump and the volume of filling up three (3) Weber 45 DCOE float bowls, but SUs have the same needs, if to a smaller quantity.

Has the time required in your case recently changed to significantly longer? If so, that *might* be a possible indicator of a leak somewhere in the system. Other than the inherent design of the fuel pump (and which type/manufacture wasn't specified) there is no separate check-valve feature in the fuel feed circuit. Since the introduction of ethanol gasoline, I've had to change out the rubber hoses a couple of times due to degradation. The last time, the hoses were supposed to be more compatible, so maybe the aftermarket is catching up...

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
rusty1c Avatar
rusty1c Peter D
Antioch, CA, USA   USA
1961 Austin-Healey 3000 BT7 "RUBY"
1963 Chevrolet C10 "Rusty"
Randy, Thanks for the description of what you experience especially with the 3 Weber's. On my car when I turn on the ignition switch on I
never experience more than 3-4 clicks before the pump has recharged the system, so that is all I had to go by. Interesting to hear what other folks are seeing.
Pete

petnatcar Avatar
petnatcar Silver Member Peter Carbone
Watertown, NY, USA   USA
I'm with you Pete.
In 46 years I've never had any major fuel issues.
Just turn on the Switch, the pump clicks for a few seconds then it starts.

No drama, thank you Jesus.

I replaced my 45 year old pump as a matter of preventive maintenance
and upgraded the plumbing but I had to laugh when I took the old pump apart.
Thank God for that little filter.

Good luck,
Peter


Attachments:
FUEL PUMP2.jpg    85.8 KB
FUEL PUMP2.jpg

DSCN3625.JPG    71 KB
Sign In or Register to view this photo
DSCN3639.JPG    35.4 KB
Sign In or Register to view this photo
Texas57 Silver Member Robert C
Stephenville, TX, USA   USA
I rebuilt the rear float assembly.. it was way out of adjustment.


~R

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster





Join The Club

Sign in to ask questions, share photos, and access all website features

Your Cars

1962 Austin Healey Sprite

Text Size

Larger Smaller
Reset Save

Sponsor Links