TR6 Carb Problem

[Govtslug]

My car is a 1970 TR6. Yesterday my car ran fine on a 1 hour drive. This morning as soon as I started it, it ran poorly, barely idling. Better at higher RPMs, but still not running well. I pulled the air cleaner off (aftermarket type with box on the carbs and filter up near the radiator) and it was full of gas. So I’m getting significant flooding in one or both carbs. Where should I look first to determine where the problem is? I’m really a novice with these carbs but I’d like to see if it is something obvious and easily fixable. Thanks!

Tom

 

[NutmegCT]

Tom - Seems strange that the air cleaner would be full of gas. Engine vacuum usually pulls air through the cleaner to the carb - not pushes fuel *into* the cleaner. First thing I'd do is check the fuel float level in the carb bowls.

Tom M.

 

[mctriumph]

The Tr6's came with some funky floats that in their old age sink. start there.
Mad dog

 

[poolboy]

More than likely the problem is with the needle valves within the one or both of the carb float chambers that's not closing when the float chamber has had enough gas.

Before doing anything pull the engine oil dipstick and see if you smell gasoline in the motor oil on the dipstick
Don't drive if you do..you'll have to fix the problem with the carbs as well as drain and replace the motor oil.

 

[Govtslug]

It doesn’t seem to have gas in the oil, so I guess that’s a good thing. I sprayed carb cleaner on the linkages and air valves. The air valve on the front carb was a little dirty. The valves moved up and down smoothly. I put the air cleaner box back on and the car started, but idle was ruff, wouldn’t stay running without a little choke. I don’t think I fixed anything. Would the next thing to try be taking the air valve cover off to see if I have a diaphragm torn?

 

[poolboy]

That OK to do but it's not why the carb flooded.
If the needle valve in the float chamber hasn't cleared up on it's own as they sometimes do you can try this:

• Disconnect the fuel line at the carbs and plug them or use a cut off valve.
• Start the engine and let it run until the carb runs dry.
• 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.
• Be persistent. Blast them again now that you know what to expect.
• 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.
• Feel free to follow up with a 20 # shot of compressed air
  

• 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 for loss of buoyancy of the floats...that can exhibit 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'.

 

[Govtslug]

Thanks Ken, I’ll give the spray and tapping a try. I’ll let you know if it improves anything!

 

[Govtslug]

Just to close this thread out, Poolboy’s suggestion worked! I disconnected the fuel lines and shot each carb with carb cleaner while the wife tap-tap-tapped the float bowls. Reconnected everything (replaced the rubber fuel lines while I was at it) and it started and idled great! I took it for a short shakedown run and it still runs fine, no flooding or leaking gas out of the air cleaner box. I think I’ll run a bottle of fuel system cleaner for the next couple of tanks just in case. Thanks everyone for the great advice.

Tom

 

[mctriumph]

Gov, you will soon be replacing the needle and seats. May as well buy them now......
MaD DOG