TR6 Bad Luck?

[poolboy]

That's it and worth a try.
Here's the procedure.

• Start the engine and let it run until the carb runs dry.(Tush's idea)
• Insert the red extension tube of whatever solvent you have into the carb's fuel inlet nipple. It does not have to be carb cleaner. WD40, PB Blaster, just about any aerosol will do.
• Blast away but be aware that most of the solvent will come shooting back at you.
• While blasting, tap lightly but rapidly with a metal object such as a box end wrench on the wall of the float chamber in order to set up vibrations.
• If you are lucky you will loosen up the needle valve.
• If not, you should completely remove the carb and open the float chamber and treat or replace the needle valve and check the buoyancy of the floats. A sinking float exhibits the same symptoms ...
• If you do have Grose jets, skip the procedure I first described and just go ahead and replace them with the original plunger type needle valves.
• Unless you are a dentist I would not recommend trying to take a shortcut by attempting to remove the float chamber and needle valve with the carb 'in situ'.

 

[pdplot]

Wish me luck. It's been bad lately. Another losing afternoon at my weekly poker game. Lost $19.

 

[Madflyer]

When you find the problem add a full can of SEAFOAM to gas tank and change the fuel filter. If you have the OEM fuel pump with prime lever remove rubber lines to carbs and hand pump fuel pump, hose my be blocked or gone bad inside hose ( anytime working with gas keep a fire EX close )

 

[TFB]

Bottom of back carb was damp. Rapped it a few times and it dried and remained dry. Pulled the back 3 plugs - they appeared to be gas-fouled, so I cleaned and wire-brushed them on my bench motor & reinstalled. No difference. Car will not idle and won't start without pulling the choke out all the way. At rest, it will rev up to 4K and probably beyond but it may not pull up the steep hills we have here under load. Roads are wet so I won't take it out of the garage until it dries off. This thing has never been driven in the rain since I've owned it. In all the 67 years I've been messing with these cars I've never dismantled or rebuilt an SU or Stromberg. Just took them on and off when necessary.

looking down at jets with domes off you can see fuel level which should be slightly below jet and equal in both carbs.Then crank over motor with coil disconnected .If level stays the same correct height you can eliminate the fuel level/float /adjustment and stuck or leaking float valves.
Tom

 

[NutmegCT]

Paul - did you charge the battery overnight on a real charger (not a maintainer)?

Are the horn and headlamps strong? Do the lights dim when you try to start the engine?

 

[pdplot]

Battery was fully charged on a 25 amp charger. All electrical items working normally.
I had to do office work this am but will get to car this afternoon and report my findings.

 

[NutmegCT]

Thanks Paul.

 

[pdplot]

Removed and plugged fuel line, shot some penetrating oil and WD40 into inlet and rapped on float chamber wall with heavy pliers. Fuel line back on, started car - no difference. Full fuel delivery to rear carb (don't ask me how I know). I guess carb will have to come off unless by some miracle the problem lies elsewhere.

 

[poolboy]

Refresh the situation for me, Paul.
Is there fuel to both carbs ?
Is there gas leaking from one or both carbs ?
Has any of the vacuum or emission hoses come loose from a carb or any other location ?

 

[pdplot]

1. Fuel to both carbs.
2. Rear carb nut under float bowl gets damp but doesn't drip.
3. All hoses connected AFAIK.

 

[pdplot]

To eliminate ignition problems, I switched #3 plug with #6 and started it. No difference, and when I removed #3 plug from #6 cylinder, it was wet with fuel. I also tested lead #6 by removing plug and holding it against block. It was firing normally. Picture of #6 plug attached. Note black center electrode. Plugs 1,2 and 3 had normal gray electrodes; 4, 5 and 6 black shiny ones like you see. Would removing the plug from the bottom of the float chamber enable me to operate the float so as to free the needle? It's supposed to be just a push fit but it has a screw slot in it.

 

[poolboy]

I,m not crazy about the kind of plug you have, but that's not the real problem.
There are 2 types of float chamber plugs. You have the screwed in. Here's some pictures. From them I think you'll see what you can or can't do by just removing the plug..

 

[pdplot]

Looks like I am screwed in as well. I think the float is stuck shut. If I pry the plug out and little or no fuel comes out, that will prove the float is stuck shut - right?

 

[poolboy]

Not so much the float...they don't tend to stick....but the needle valve, that's another story.

 

[pdplot]

I meant needle valve. Back in college, I rebuilt a GM carburetor from a Pontiac or Olds (I forgot which) belonging to a fraternity brother and called the needle valve an "elk's tooth".

 

[poolboy]

If you just want to see if there is gas in the float chamber there's an easy way.
Get a soda straw and blow into this nipple... OR if you have a pre 73 carb, into the round unthreaded hole (brass in this picture) in the carbs air box mounting flange.....while lifting the air valve up with your finger.
If there's gas it'll bubble up under your finger.

 

[Derekmcallister]

I had a stuck float (needle) valve that would not open consistently and the car ran as you describe (and the ignition wire test gave the same results as what you've experienced). It was a recent replacement as part of a rebuild that I did, so I swapped the old one back in and it worked properly. The new valve went straight into the trash. Hopefully the "blast it" method will clear any crud that is causing your valve to stick!

 

[pdplot]

The back carb has to come off - a miserable, stinking job, working blind with sweat running down my face 1/4 turn at a time with an open-end wrench. I've got 3 of the 4 nuts loosened or off and the choke, gas line and emission hose disconnected and I loosened the linkage connecting the throttles at the back carb end but it's not budging. Before I ruin something, do I have to loosen the other two screws so I can slide the flex part off the back carb so I can remove the carb? As usual, the manual is no help.

 

[poolboy]

You have to have all 4 nuts and washers off the studs where the rear carb hangs AND the bottom left nut and washer from the stud on the front carb..Then you can swing the throttle linkage mounting bracket out of the way so that the rear carb can be removed from the studs.
As far as the carbs' throttle shaft linkage, you really just have to loosen one end of the coupling that is attached to the rear carb's long throttle shaft, but you can loosen both on the rear carbs throttle shaft and slide the coupling over the long shaft.

 

[poolboy]

This shows the bracket and why it has to be removed from the studs on both carbs.