Fuel Fittings at pump and Aisin carb (1 Viewer)

[JohnJL]

I messed up my hard line fitting at the fuel pump side by crossing the threads. I'd like to replace the line with a soft AN line with fittings at both ends. I would really appreciate if someone could confirm the measurements/fitting size at the fuel pump outlet side, and at the carm inlet side. Below is a pic of the adapter fitting at the carb inlet side at the top and the fuel pump 90 degree elbow at the bottom. I'd like to find a -6AN to ? size fitting at the carb. Ideally it would be direct to the carb (~9.8-9.6mm tapered), but the larger size (~12.6mm 1.5 threadpitch straight) on the adapter fitting would be OK too. Could someone please confirm the fitting sizes input to the fuel pump and inlet to the carb?

The pump is a new OEM and the carb is original to the 1974 FJ40 US market F1.5 motor (Jan 1974)

Thanks!

 

[73FJ40]

The threads on the fitting into the fuel pump are 1/8" BSPT. (British Standard Pipe Tapered). It's likely that's the same thread into the carburetor.

 

[thebigredrocker]

Someone makes a 1/8" male bspt to -6AN male. Don't recall the source at the moment.

 

[JohnJL]

Thanks guys! I am going to add a filter, nice idea.

Anyone able to confirm what thread measures 12.6mm or 0.505" OD on the threads with a 1.5 threadpitch? Thats what the banjo fitting has, I'd like to retain that banjo bolt and adapt to a straight -6AN fitting.

Thanks!

 

[GA Architect]

View attachment 2226110

1/8-28BSP & 13x1.5mm

Click here, I think post #10 has the part number of what you are looking for.

 

[thebigredrocker]

@JohnJL
Here is the -6AN x 1/8" BSPT I used on the carb inlet and OEM fuel pump

 

[thebigredrocker]

Here's another shot of the custom redneck fuel filter mount. Note it shares air filter mounting bolts

 

[JohnJL]

Thanks guys! Summit parts arrived in 2 days...here are some pics of the parts and numbers if others want the same.

Another stupid question...my disassembly pics show the line I am pointing to as the feed from the fuel pump. However I found the banjo fitting has a screen on the bolt, what I would expect to see on the feed side (why would there be a screen on the return side?!?!) Can someone put my mind at ease that the one I am pointing to is indeed the feed?

Thanks!

 

[JohnJL]

Here's a standoff bracket I made for the filter...

 

[73FJ40]

@JohnJL

Thanks guys! Summit parts arrived in 2 days...here are some pics of the parts and numbers if others want the same.

Another stupid question...my disassembly pics show the line I am pointing to as the feed from the fuel pump. However I found the banjo fitting has a screen on the bolt, what I would expect to see on the feed side (why would there be a screen on the return side?!?!) Can someone put my mind at ease that the one I am pointing to is indeed the feed?

Thanks!

View attachment 2230702

View attachment 2230703

View attachment 2230704

The parts fiche illustrate that the banjo fitting IS the return line. Note that the supply line tubing is the same routing for earlier models that didn't have the return line, in concert with apparent Toyota philosophy to avoid churning up too many part numbers.

 

[JohnJL]

Thanks so much!
So weird to have a filter screen on the RETURN side...

 

[thebigredrocker]

The one on top is the return line. The bolt that screws down thru the banjo has a very small brass restrictor in it, which would not serve well for fuel delivery.

Besides, if you think about it, since the gas flowing thru the restrictor would be INSIDE the open-top filter screen, it would make the screen pretty pointless.;p

Too late on a Saturday night.:sleep:

I'm glad it appears to be fixed once again.

But the fitting w/ the tiny hole is the return banjo. Yes, it has a rubber check valve /pressure regulator built into it. It appears to be facing the wrong way, as you observed, because it is the fuel return, not the inlet. It may have been plugged w/ a piece of dirt (common). but that doesn't cause the carb to run out of fuel.

You might want to remove the fuel inlet fitting and look back into the carb at the inlet screen, to see if it is coated w/ poo. That could cause the running out of fuel under load symptom.

 

[73FJ40]

@JohnJL

I think your screen has pushed itself up into the return line.
Note that in the illustration below, the "pre-return line" arrangement of fuel screen (to the left of the (7302-7501) box) has the same screen being held in place by the "plug 21785." That's the arrangement on my 7301 carburetor.

My opinion is that Toyota came up with the banjo fitting to replace the plug as an easy way for fuel return without having to trash a bunch of carburetor castings.

 

[LCNuts]

I was able to find the 1/8 bssp to 6an on Amazon. I just changed out my flex lines this way. They are available on Ebay as well but ship from the UK.

Amazon product ASIN B081TSH54R