I like 8pack's idea. With a mechanical valve or two you can basically have two separate fuel systems. Exercise them now and then and you'll have about as reliable a fuel system you could ever hope for on an old truck.

 

Years ago I had a '67 F-100 that had a petcock setup in it with the valve handle extended up through the cab floor just to the left of the drivers seat. I could run one tank dry (I def. tried not to) and switch to the other tank while rolling. Pump the gas, roll start the 3-on-the-tree (w/ tailshaft OD that complicated the roll-start, but that's quite OT), or bump the starter while out of gear. The ol gal's 352 FE would sputter back up, backfire once and go-go-go again.

I bought the truck built and never totally figured out the systems installed, but in keeping with the previously mentioned mechanical system being gravity-fed to prime the mechanical pump, this valve was in-line with no air trapping high points in the run.

Man that was a fun truck. Nearly doubled my money on the deal and didn't drop a dime other than gas and oil into it.

Good luck keeping Ethyl going the distance!
JML

 

Hi Gary!
. I love reading about ETTT. You had a question about why your mechanical fuel pump wasn't drawing fuel from your new tank when the power disconnected from your new electric pump. My gut feeling is the suction from the mechanical pump can't overcome the restrictions being caused by the non functioning electric pump or the fuel regulator. But I could be wrong.
A couple of other suggestions maybe not worth anything:

About not being able to see if your carb is getting fuel with your air cleaner on. I would look at using a see through fuel filter such as a NAPA 3001. That way at least you would know if there is fueling going to your carb.
After you determine your final design, think about adding a return line with a restriction back to your fuel tank as close to your carb feed as you can get. That way when the engine us shut off and is in heat soak, fuel could expand back to the tank, and hopefully not expand past your carburetors needle and seat flooding out your engine making it harder to start.
Anyway keep us posted!

 

Thanks again. . REALLY I want only to have my new 45 gallon gas tank supply gas to the engine. I WOULD like to choose BETWEEN using the mechanical fuel pump and the Electric one. Isolate each from the other. Im trying to use the single fuel line but have each pump work when I want it to. I dont really want to run a separate fuel line from the tank to each pump.

In the event I cant isolate each one's function from the other,. Are there any concerns about pushing 4psi of fuel from the electric fuel pump to the inlet side of this functional mechanical fuel pump for efforts like priming the carb fuel bowl? Is there some reason to consider having both pumps function at the same time other than to prime the Carb?

. I will be using the very small for the size of this truck (20 gallon) original gas tank to INSTEAD hold diesel fuel for my 8kw DIESEL powered Generator. It hangs on the frame rails on the driver side across from where I have mounted the 45 gallon tank onto the passenger side . Now that I know my new 45 gallon tank that I purchased off of Ebay as military surplus functions, ill be disabling the small tank for motive engine power.

With that gas tank out of the picture, all of that "my electric pump is filling the small gas tank" stuff is not relevant. I originally only mentioned it was being filled up with gasoline from the electric pump because I was surprised that this is what occurred and to show the trials Ive experienced

. Only 4psi is coming out of the regulator. I thought the mechanical pump function would help direct the flow of gas away from that part of the "T" that the hose running to the small gas tank connects to. It also is surprising to me that this small tank filled up because it was already mostly full before turning on the electric pump. I thought its own full tank pull of gravity would be enough not to have any additional gasoline fill it. Like I said its not a thing to lament on,. that hose leading from it to the "T" is clamped off.so that tank cant fill or supply from that hose now.

.I dont like the fact that mechanical pumps have failed me so often. The vacuum operated windshield wipers are powered by this mechanical fuel pump so I want to keep it functional. Ive made small consolations about retaining the original engine bay bare bones look but I dont want to do more than I have to to change its look. The new fuel pressure regulator mounted on the passenger inner fender well next to the voltage regulator and some additional fuel lines changes how it used to look. A big visual change is the shinny chrome plumbing and silicone elbows I added to my oil bath air cleaner. The look is way different to the black accordion "slinky' spring type, thin cloth like, floppy hose that was used originally. Short of that no other visual stuff exists to show any modifications.. The mechanical fuel pump stays for looks if not for looks and function. I could remove the internal lever to disable it but then I wouldnt have vacuum for my vacuum powered windshield wiper motor. I dont mind that it is there, when it is working the engine runs fine. I just want a back up to it.

Y'all, No more worries about a 2nd tank. Pretend I only have the 45 gallon one.

I have wired a toggle switch to the electric fuel pump so it functions only when I want it to.

 

Very dangerous to run an electrical fuel pump from a toggle switch. Needs to be either relay activated by oil pressure or a time delay relay. If in an accident the fuel is going to run all over the place and never shut off. 45 gallons is a huge hazard

 

I should consider that see through filter. I think I did not do that originally because I didnt see (no pun intended) the need for one because I have had those fuel filters leak. Now that I see the need, Ill add one and make it a maintenance thing to periodically replace the "O" rings to keep leaks away.

Ill learn about what to do for that return line with the restriction you suggested. With your mention of the overrun of the carb needle and seat, I am reminded that I read about that somewhere else. I think Ive even read someone had a fire from that happening....So if my original post did nothing else it did prompt this nugget about flooding to surface....Thank you.

I love story telling So posting here on FTE works for that. AND as a tremendous resource for me. Its likely I could make more money if I didnt spend so much of my day with customers relating some story or another and instead focused on moving to the next shop....but I love that type of interaction and they know they can always count on something from me to break up the stress of the day for them....Its fun....So relaying the adventures of ToolmanGary and ETTT are on!

 

Kevin I neglected to also say I have a impact sensitive type of switch I took from a Ford Escort that is wired in there also so if there is an accident the pump doesnt have power to it. I will also look into a time delay relay also. Thank you.

 

Hey, Hey, Gary! I like the paragraphs! Much easier to read.

I can't help you with your problem. It sounds like you got it figured out by now.

 

Hey Gary,
. I need to correct myself about a fuel filter I recommended. Since you probably have 5/16" lines I should of asked you to look into the NAPA Gold 3002, or a Wix 33002. Its a one piece see through plastic filter so no messing around with O rings. Its about the same physical size of the filter you use now.
. As far as the stories go, please keep them coming! I wish we could go for coffee. You would have to hear mine too! LOL
Edit:
Sorry you probably have 3/8 inch fuel lines, in that case ask for the NAPA 3003 or Wix 33003.