2 Barrel F Carburetor - Tech Guidance Needed (1 Viewer)

[Archie 1962 FJ25]

Cross post from 25 forum -

Hello All Carburetor Guru’s -

This is what I am planning on using it on my 1974 F.5 Motor. As per stamped date it appears 1971 or 81 (if a replacement). Now carburetors are a complete unknown territory for me and honestly I know nothing about them. So all and any guidance will be highly appreciated.

What I want to know (before I start spending money on rebuild) -

1) Is it a good carburettor to spend money on?
2 Is it missing anything that I should source?
3) Does it have fuel return option?
4) What parts would I need to modify it to suit my FJ25 accelerator linkage?
5) How should I hook early choke & throttle cables?

Any other information that I should know before taking it for rebuild?

Thanks in Advance,

Archie

 

[Dizzy]

You will spend more time than money. A disassembly is needed to see its condition.

Jet access plugs look unusual.

Don't even try this without buying a JIS screwdriver. You will also need a Base Plenum for the PCV from the crankcase.

It looks more like an F carb, with no internal fuel-return option. That poses a question, where did the throttle plate cast iron section get the ported vacuum barb? Hence, it doesn't appear on the SOR Carb Identifying chart? 9/73 to 1/75 should have an EGR insulator plate, so I wonder if a USA '74 air cleaner will be too tall?

Choke cable screws on to the part (external) on the end of the butterfly shaft. You also have something to clamp the sheath on. Try mocking it up for overall length and fitment.

The carb uses an accelerator cable instead of linkages, so it might work, but I've also heard of aftermarket options. Try mocking it up with the carb on the intake and the cable from the firewall. You might need something to attach a throttle return spring to, but I can't really say one way or the other.

 

[Archie 1962 FJ25]

Thanks @Dizzy , that Carburetor is non USA. Bought here in NZ so linkages may be relevant for RHD application. I have seen all the FJ40’s (1971 onwards) here in NZ have cable type linkage. However it will be fitted into LHD FJ25 with stock mechanical linkage. (Linkage rods etc)

My motor is 1974 F.5 and that is why I was worried on fuel return aspect. But looks like it can be avoided unless it’s a must have feature. Besides I am going to use early fuel pump with hand primer so I believe that doesn’t have fuel return line anyways and fuel tank won’t have that provision too.

 

[Dizzy]

If you don't have a fuel return line on the carb, then it shouldn't make much of a difference. Float needle pressure is not really documented, so go with what works. But, fuel pumps fit precisely on the camshaft, I'd be more concerned about the lobe that they are run by. I'm at high altitude, and it isn't easy to find gas without 10% ethanol, so a fuel return line is a great feature, but not a deal breaker.

Regarding accelerator linkage, post up some pics of this LHD 25. Pedal and a couple sides of the firewall. Was your truck absent of a carb and motor when you bought it?

Does your air cleaner need a threaded rod out of the top of the carb?

 

[Archie 1962 FJ25]

Yes my FJ25 was bought in LA and came with a Chevy 292 straight six. I got rid of that and put in 1974 F.5 (Last of F series motor). F.5 motor has more similarities to 2F and PO of this motor installed 1978 2F carburetor on it that has rod coming out for securing Air Cleaner.

In its stock form F.5 motor should have an air cleaner box that clamps around the Carburetor similar to all prior years double or single barrel set ups. I have sourced the correct air box as well.

I am trying to take it back both motor and FJ25 back to their respective stock form (as much possible). In fact PO has located my original matching number motor also and saving it for me in Studio City, California. I am looking at cheapest possible options to bring it here but that may take some time. Plan is to rebuild that motor slowly while driving with current motor.

I will take some pics and post here shortly.

 

[Archie 1962 FJ25]

This is the linkage I am trying to work with.

I also have 2 more linkage rods that were stock for using with early SD 40 Carburetor. I just could find them today in garage.

 

[Archie 1962 FJ25]

Firewall and the current 1978 carb on the 1974 motor.

 

[Dizzy]

From the little information that I could gather, the SD40 throttle would be operated from a push-pull from below. I haven't a clue as to what you would mount the bellcrank on to for the current motor. However, I don't know much about the 25 setup either. This is going to be a tactile one, unless you find someone who already is experienced. At least, you have the ball end that would be attached to the 25 carb, fabricating something on the end of the throttle shaft for the 2 bbl F carb might not be too difficult, and then you only need to locate the bellcrank on something. A couple things are for certain, a throttle butterfly only turns so much regardless on carb, and the throttle shaft spindles seem oriented the same general location for the early carb and later carbs.

I keep thinking that the easiest would be a cable set-up since that is what the carb has already. Either OEM, a salvage-yard vehicle, or aftermarket like for an Aisian, Holley, or Weber. However, I also realize that it might not be good advise drilling the required holes in the firewall for it either.

 

[Living in the Past]

Think it was around fifteen years ago I modified my 65 FJ45LP-B to a cable when I switch the carb. Can't even remember what was in there. I know it wasn't stock. Has a early 2F in it. Used the accelerator pedel from a early seventies. Needed drill a couple of holes in the firewall. Being you not running the original engine anyway wouldn't worry about keeping the stock pedal. Anyone who could be fooled by a later F155 isn't going to notice the non stock pedal.

 

[Archie 1962 FJ25]

Anyone who could be fooled by a later F155 isn't going to notice the non stock pedal.

No chance of being fooled here for anyone. I will make sure they know it’s a late F155 transition motor, IMOP this motor is legendary and way rare than any other cruiser motors in character. Its in there by choice after searching hard for almost 3 years in NZ.

Original motor will be rebuild over the time but will be put in only when my FJ25 is ready for a museum or next owner. I am in no mood of driving it with its stock motor.

 

[Archie 1962 FJ25]

From the little information that I could gather, the SD40 throttle would be operated from a push-pull from below. I haven't a clue as to what you would mount the bellcrank on to for the current motor. However, I don't know much about the 25 setup either. This is going to be a tactile one, unless you find someone who already is experienced. At least, you have the ball end that would be attached to the 25 carb, fabricating something on the end of the throttle shaft for the 2 bbl F carb might not be too difficult, and then you only need to locate the bellcrank on something. A couple things are for certain, a throttle butterfly only turns so much regardless on carb, and the throttle shaft spindles seem oriented the same general location for the early carb and later carbs.

I keep thinking that the easiest would be a cable set-up since that is what the carb has already. Either OEM, a salvage-yard vehicle, or aftermarket like for an Aisian, Holley, or Weber. However, I also realize that it might not be good advise drilling the required holes in the firewall for it either.

Good suggestions here. Cable linkage would be a lot easier and under consideration. Although It will be perfect if it can be matched with original or similar stock mechanical linkage and I will explore all the possibilities.

You are right with this transition F155 Toyota deleted the pre drilled location on the block to mount bell crank. However there are couple of spots in similar area on the block that seems like filled from the factory and wonder if I can drill there to bolt bell crank. I have FJ25 push / pull linkage rods as well.

 

[4Cruisers]

By any chance did you modify your linkage yet? If so, did you retain the bellcrank shown in your Post #7, or are you not using it? I'm searching for that exact same set-up for my '71 FJ40. If you're not using it please let me know if you'd be willing to sell it. Thanks.