Fuel Draining Back? NO!

[StevenH]

I tried insulting my fuel lines and they just sat there and looked at me funny.

At least they were not talking back.

After telling my fuel lines they sucked... I insulated them.

[autostick]

Dan, you may be misled as I think he was referring to a Vulcan insult.

...so I insulted the existing line... with something called Vulcan

My apologies for vulcanized drift.

[TonyC]

Wait...I thought Vulcans weren't liars!

[Precision1]

I had a similiar problem with hot starts. Turns out the accelerator pump diaphragm would leak when the engine was hot and drain the bowl. The battery would die before I could get enough fuel back up to start. A couple shots of ether was needed. Replaced the diaphragm and all is well.

[NicSanford]

I'm thinking about removing the rubber diaphragm from my newly rebuilt Carter 3 port, replacing it with a rubber gasket, and removing the FP pushrod. Then, installing an EFP under the left front wheel well, behind the protective plate as did autostick, and just having the MFP to maintain the original appearance, and as a pass through. Has anybody else tried this? Also, when it comes to annual meets or shows, will this configuration reduce points, or is that only if the pump can be seen? The solution here seems obvious to me if you want a driver, but if it reduces points for those in competitions, I can understand the concern...

[NicSanford]

AHA! After thinking on using the MFP as a passthrough, I also thought that this would still allow us to utilize the fuel return line to balance the pressure. Damn I'm good...

[Mike-Casella]

Better think this out a little more. If you remove the diaphragm from the pump, any fuel that enters the pump will go directly into the oil pan. If you want to use the pump as a pass-thru unit, don't remove anything from the pump itself. Removing the push rod isn't such a good idea either, the diaphragm in the pump needs to flex in order to keep it from drying out and eventually cracking leaving the fuel that passes thru nowhere else to go but the oil pan again. My suggestion would be to just leave the mechanical pump alone, it's not going to bother anything.

Mike

[Mike-Casella]

Sorry, I just re-read your post. If you replace the diaphrahm with anything, make sure it is ethanol resistant material like "Buna-n" or "Viton".

[navguy12]

Also, when it comes to annual meets or shows, will this configuration reduce points, or is that only if the pump can be seen? The solution here seems obvious to me if you want a driver, but if it reduces points for those in competitions, I can understand the concern...

If hidden from view, you are good to go.....

[NicSanford]

Better think this out a little more. If you remove the diaphragm from the pump, any fuel that enters the pump will go directly into the oil pan. If you want to use the pump as a pass-thru unit, don't remove anything from the pump itself. Removing the push rod isn't such a good idea either, the diaphragm in the pump needs to flex in order to keep it from drying out and eventually cracking leaving the fuel that passes thru nowhere else to go but the oil pan again. My suggestion would be to just leave the mechanical pump alone, it's not going to bother anything.

Mike

Actually you make a good point. Shortly after posting this, I thought it would be easier just to remove the two spring valves from inside the pump rather than the diaphragm. This would let fuel pass through while using the fuel return to balance pressure, atleast from how I can see it. Thoughts?

[Mike-Casella]

By removing the valves altogether, the fuel will have nothing to stop it from draining back down the line. Why not just use the electric pump as a back-up, and let the mechanical pump do what it was made to do. I suggest that very thing quite often.

[NicSanford]

By removing the valves altogether, the fuel will have nothing to stop it from draining back down the line. Why not just use the electric pump as a back-up, and let the mechanical pump do what it was made to do. I suggest that very thing quite often.

Vapor lock. I'd rather use an EFP as my primary to avoid having to rig an activation switch, or bother with turning it on and off. I'd like to just get in and go, and drive without any extra steps just to prime. I'm seriously considering the rubber gasket option...

[NicSanford]

And, the drain back port won't allow it to drain unless it reaches a certain pressure, so I imagine this configuration will be like having an EFP with a 3rd port...?

[NicSanford]

Are there EFP's that stop fuel from passing backwards through it?

[Mike-Casella]

The By-Pass port fitting, if it's still the original one, was actually designed to open when the fuel reached a certain temperature. It's purpose was to keep cool fuel flowing thru the pump to keep the pump from going into a vapor-lock situation. If you let the fuel flow thru the pump by using an electric as a booster, the by-pass will still work. If you use the electric all the time, there would be no need for the by-pass circuit at all.