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Photo of carburetor needed

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M

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Apparently in an attempt to save money (sometimes good... sometimes bad), a former owner of my car substituted a front jet lever link (with choke cable arm) for the rear jet lever on my SU type H carbs. It is pointless there because the jet lever link in the rear doesn't attach to the choke cable.

I want to replace it with the proper rear jet lever, but the way it has all been jerry-rigged to work, I'm not exactly certain how the thing should look when properly assembled.

Can someone send me a photo of a rear carb showing the levers and links properly assembled? The exploded diagrams in the manuals show me the components, but not how they should fit together.

I can guess, but I'd rather not.
 
Ed - hope this helps:

TR3%20choke%20linkage.JPG


Tom
 
And this:

20070602.jpg


T.
 
Tom,

Great! Just what I needed. You won't believe the spaghetti-nature of the arrangement that is now on the car. It's only redeeming feature is that it apparently works. I'll be glad to get it back to the way it should be. That out-of-place choke arm rubs against the fire wall.

More disturbing, however, is the fact that several of the pins that take cotter pins to hold them in place were installed without cotter pins. Friction, I guess, was the only thing holding them in place.

Many thanks!

PS. We have a lot in common: history, languages, travel... and classic cars. I was even a teacher... And I once lived in Connecticut. Small world.
 
Tom,

On closer inspection, it appears that there is an extra clevis pin on your jet lever link. The one pictured in the Moss catalog only has two: one at top and one at bottom. Yours has a small one just above the bottom one. Is that some kind of a stop for the jet lever and not shown on the Moss picture?

I'm also a little confused how you have your rear jet lever attached to the rod end fork. It appears to be on the side of the fork rather than between it.
 
Ed - if you were missing several cotter pins, your carbs were just staying together out of habit! Glad you found what's missing.

Note that there are "varying interpretations" of where to put that u-shape fork (yokr). Some folks have the u-shape fork behind the pin, some around the pin, some on the fender side of the pin. Here's one thread which discusses this:

https://www.britishcarforum.com/bcforum/ubbthreads.php/ubb/showflat/Number/658970/

By the way, on the front carb choke assembly, you have to be careful that you don't set it up so that it scrapes the wiring harness covering. Exposed (and touching) wires are not fun!

Tom
Edit: by the way, the color photo is from someone else's earlier post. Not my car (but it is my setup).
 
Hi, Tom,

Many thanks. I'll take a look at the thread on where to put the u-shape fork. Seems that there are always a variety of ways to accomplish a task on these cars. Nothing simple about these "simple" cars, n'est-ce pas?

I don't plan to do anything with the front carb choke assembly, but I will look at it carefully to make sure it is not scraping the wiring harness covering. Thanks for the warning.

Again, many thanks.
 
NutmegCT -- Tom

In looking more closely at the photo you kindly provided above, of the rear jet lever assembly, I notice that there is no fast idle cam linkage shown. Looking at the MOSS catalog and other manuals, I find that there should be only one fast idle cam and linkage, at the front carburetor. But my car has two fast idle cams, one front and one back, and therefore two fast idle links

Did some of the early TR3s have two fast idle cams? Or, perhaps, was an extra cam added to this car by some previous owner for some reason?

Is there any advantage to having two?
 
Hi Ed - just to be clear, as I said earlier the color photo isn't my car. That came from one of Nick Morgan's posts. Maybe you could send him a PM for more info on that setup?

By the way, in looking through my original Service Instruction Manual for the TR2/3, I found some interesting details on the linkage hardware which I'll post in a new thread.

Tom
 
Hi, Tom,

I recall that you said that the photo wasn't of your car, but that you had the same setup.

Perhaps after 1958 only one fast idle cam was put on the car, although I haven't found mention of this in the official list of changes made to the various models. Mine is an early 1958 TR3A.

I have a copy of the Service Instruction Manual that you are speaking of. Some of the details to the linkage hardware are a bit confusing to me, not only because the names are differenct, but some items are mentioned in the text but not shown in any of the illustrations.

Many thanks for your information.
 
Me again.

Take a look at the S.U. Carburettor Details chart (Fig 10) on page 21 of the Service Instruction Manual, Fuel System section.

The manual is for the TR2 with H4 carb, but it does show that the rocker lever (#30), washer (#31), rocker lever bolt (#32), spring washer (#33), and connecting lever (#34) are only for the front carb.

The SIM supplement for the TR3 says that H6 carbs are fitted instead of H4, and aside from the different jets, "[t]he instructions given for the H4 carburettor as fitted to the TR2 apply to the H6 type apart from the four-point mountings."

Again, my rear carb (H6) is set up the same way as the one in the color photo, but that's only because it's the way it was when I bought the car. Seems to me that if the SIM for the H4 shows only one "fast idle cam" mechanism, on the front carb only, then I don't have a clue why there would be one on the rear of an H6.

Far wiser minds than I will hopefully comment on this.

Tom
 
LexTR3 said:
NutmegCT -- Tom

In looking more closely at the photo you kindly provided above, of the rear jet lever assembly, I notice that there is no fast idle cam linkage shown. Looking at the MOSS catalog and other manuals, I find that there should be only one fast idle cam and linkage, at the front carburetor. But my car has two fast idle cams, one front and one back, and therefore two fast idle links

Did some of the early TR3s have two fast idle cams? Or, perhaps, was an extra cam added to this car by some previous owner for some reason?

Is there any advantage to having two?
Click to expand...

LexTR3 said:
Apparently in an attempt to save money (sometimes good... sometimes bad), a former owner of my car substituted a front jet lever link (with choke cable arm) for the rear jet lever on my SU type H carbs.
Click to expand...

Could it be that a PO installed a front carb on the back?
 
Twosheds: "Could it be that a PO installed a front carb on the back?"

Hi John - isn't the front carb the same as the rear carb? Other than the fast idle assembly and throttle/choke linkage?

I see on my rear carb there's a mounting point for that "fast idle cam", but of course it's unused. I'd think that having two of those gizmos would make setup and adjustment of fast idle more problematic.

(I'm about to send you a link to some great Boneyard aircraft pics from the 1960s.)

Tom
 
Hi, Tom.

I should have written "front carb linkage" instead of "front carb". Will you ever forgive me?

Great, you're behind in sending me airplane photo links. I'm looking forward to seeing some more airplane photos.

No word from Mike the Mad Rocket Scientist about the B-47 ferry flight photos. Oh, well...
 
Tom and Dr. John,

You are right, any carb can accommodate the "front carb linkage" (or "front jet lever link"), the linkage that has the arm extended to hold the choke cable. The rear carb linkage (or "the rear carb jet lever link")doesn't have that arm.

My car, for some unknown reason, had a "front carb linkage" on the front and the rear carbs (the rear one was not attached to the choke cable). Since this looked very strange and useless to me, I have taken that "front carb linkage" off the rear carb and substituted the proper linkage.

Moreover, there are two fast idle cams and links on my car. One linked to the front carb jet lever, and the second linked to the rear carb jet lever. This was my question: Why two, since all the photos I have seen and manual descriptions mention only one.
 
Hi Ed - I'm as stumped as you. Have no idea why there would be one of those setups on your rear carb.

However ... when you look at that H4 diagram on page 21, you see there are two *different* jet levers (#23 and 24). Moss shows the same thing for the H4 in their catalog. The rear carb lever has only a single hole at the bottom (etc.).

But Moss shows the *same* jet levers for the front/rear on the H6 diagram in their catalog. I bet that somewhere along the line, Standard-Triumph decided to just use the same jet levers (cost savings?) on the later TR3.

Obviously, as the throttles are linked, the front cam in use opens both the throttles, so no rear cam setup is needed.

Totally a guess here, but maybe in the past, a previous owner saw that rear carb with the "dual hole" jet lever, and rigged it up to match the front carb.

Tom
 
LexTR3 said:
Moreover, there are two fast idle cams and links on my car. One linked to the front carb jet lever, and the second linked to the rear carb jet lever. This was my question: Why two, since all the photos I have seen and manual descriptions mention only one.
Click to expand...
Just like John said, you have two "front" carbs. They are very similar, but not identical (actually have different part numbers from SU). One of the differences is that the front carb is drilled and tapped for the advance line, while a normal "rear" carb is not. You might want to make sure it is suitably capped off, if the hole is there.

BTW, the jet levers are the same for H6 carbs. I forget offhand what is different, but I believe the levers were actually different for H4.
 
Tom and Randall,

I missed the difference in the front and rear jet levers in the Standard Instructional Manual. You are, of course, right that the front one has two "holes" -- actually one is not drilled out -- and the back one has only one. In the Moss catalog, however, both levers are the same: two "holes" -- again, one not drilled out

The front carb is tapped for the advance line... while the back carb is not (the hole -- both holes -- are plugged). I guess I meant to say that the carbs are a little different (one tapped and the other not tapped), but I understand that the piston/suction chambers can be switched, as long as the piston goes with the proper chamber.

Why there are two "fast idle" cams, links, and adjustment screws, I don't know. Other than presenting a bit of a mystery, however,I can't see that they are hurting anything. Perhaps they are there, like the two slow idle throttle adjustments, so that each carb can be adjusted separately.

And why a previous owner would have put a front carb link on the back carb doesn't make any sense at all because the arm that normally attaches to the choke cable was attached to nothing. Perhaps he had one on hand and not a rear carb link, so he used what he had.


Just returned from a road trip -- 80 degrees around there today! -- and the car ran better than ever before. Yesterday I balanced the carbs and set the mixture. With luck, I am ready for "driving season" and won't have to fiddle with the car for a few months (wish me luck).
 
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