Fuel pumps with triple Webers

[conedodger]

So after rebuilding my Webers, I am having a problem with getting the car to rev at tip-in of the throttle plates. I added back in a stock mechanical fuel pump and at the tank I have a non-stock electric fuel pump. Previously, the fuel return line was blocked off and the fuel was dead-head banjo'd into the last carb. I now have the fuel returning to the tank.

I have no choke set-up so it is cold blooded as hell until it warms up.

What are you other guys with triples doing? Silverstreak is using an RX-7 E-pump at the tank. Some seem to think that the mechanical pump can't be used because it can't feed the triples. Others say they run the mechanical in addition to the E-pump in order to feed enough fuel to the triples.

Could be nothing at all is wrong with my fuel pump situation and I just screwed-the-pooch on the carb rebuild!

[idoxlr8]

A good thread going about exactly this issue here;

http://www.classiczcars.com/forums/showthread.php?43883-Suggest-a-cheap-quiet-fuel-pump-for-my-triples.&highlight=fuel+pumps

Hope this helps.

Dean

[240ZGL]

I'm running a Facet low pressure pump 2-4 psi. Works great, no regulators, no special fuel rail setups, no problems. It's the old Bendix type, that the factory copied when they needed a reliable pump. Triples really don't suckup that much fuel.

[madkaw]

Can you elaborate on the "rev at tip in"? So are you saying that car stumbles at initial tip-in? Or just reving it up in the garage. I would think at initial tip-in you would have plenty of fuel in the bowls, it would be prolonged loads that would drain your bowls with an insufficient pump.

[beermanpete]

I agree with Steve. An off-idle stumble is likely due to a lean idle mixture or a problem with the accelerator pump(s).

[240ZGL]

Sounds like a carb problem, maybe not enough transition jet or it's just cold and they don't do well when there cold.

[cygnusx1]

I am sure you adjusted the float levels by bending the tabs right? Good. Next, you must confirm fuel level in the bowls. With the "hats" off the carbs, you can use a homemade dipstick. Low fuel level will make the fuel come into the engine later.

BTW Throttle tip-in issues are at the top of the triple weber problems list. There are solutions and it's imperitive that your throttle plates are stopped in a position NOT exposing the progression ports.

Edited October 24, 2011 by cygnusx1