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TR6 Sputtering along

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FR Burkhart

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Somehow I have created a problem I can't resolve. On my TR6, it sputters both starting from a stop and at higher RPMs. Could it be the metering needles? The Stromberg 175 CD-2 carbs are set to maximum rich as anything less leads to stalling. Spark plugs checked and replaced 2 months back, timing checked and set by a local British car shop, replaced distributor cap and rotor (electronic ignition), installed new electric fuel pump. What am I missing? Could it be vacuum setting?

Thank you for any guidance.
 
Have you checked the fuel filter? Is there sufficient flow to the carbs?
By the way, welcome to the British Car Forum.
 
I have to ask....please describe in detail what you did to set the mixture ?
 
Gliderman8 said:
Have you checked the fuel filter? Is there sufficient flow to the carbs?
By the way, welcome to the British Car Forum.
Click to expand...

Elliot,
Just installed a new electric fuel pump with filter. Pump is rated at 3 psi. I have also replaced the needle valve and carburetor float on the rear carb (haven't touched the front carb).

Thanks for the welcome. I can't imagine a better place to get advice.
 
poolboy said:
I have to ask....please describe in detail what you did to set the mixture ?
Click to expand...

I have adjusted the metering needle to max clockwise. Even at that setting, raising the piston slightly causes the engine to almost stall (drop of RPM). I tried using the vacuum tool but couldn't get enough airflow - as soon as the tool was pressed against the carb, the engine stalled.
 
One other item - oil is not remaining in the dashpot. When I add oil up to the top ring, the oil will be gone within a couple days.
 
Whatever the problem, raising the needle to maximum height is really just an attemt to compensate for an underlying problem.
I'd put the needle in the middle of it's adjustment range and try to find the actual problem.....1 and 1/2 CounterClockWise from Fully ClockWise.
I've never been able to get satifactory results with a UNiSYN type of synchronizer on ZS carbs...It blocks some ports in the carbs' air box mounting flange.
And while I see your point about the damper oil level, I'm not sure you are filling just the damper well properly when you refer to the 'top ring'
See this: ZS carb Damper level 002.jpg

There's an adage:
"90% of carb problems are ignition problems"....with that in mind I think I'd check the ignition timing at idle if only by ear...you can't be that far off.
 
poolboy said:
Whatever the problem, raising the needle to maximum height is really just an attemt to compensate for an underlying problem.
I'd put the needle in the middle of it's adjustment range and try to find the actual problem.....1 and 1/2 CounterClockWise from Fully ClockWise.
I've never been able to get satifactory results with a UNiSYN type of synchronizer on ZS carbs...It blocks some ports in the carbs' air box mounting flange.
And while I see your point about the damper oil level, I'm not sure you are filling just the damper well properly when you refer to the 'top ring'
See this:View attachment 64372

There's an adage:
"90% of carb problems are ignition problems"....with that in mind I think I'd check the ignition timing at idle if only by ear...you can't be that far off.
Click to expand...

Great suggestions. I can try these tomorrow morning. At least, the car isn't my daily driver. But it is summer and some longer road trips would be fun.
 
And...carefully just put the oil in the damper well; it's the smaller diameter cylinder that you see when you unscrew the damper knob/piston
The Owners Manual recommends using the same oil and viscosity that you put in the TR6's engine.
 
poolboy said:
And...carefully just put the oil in the damper well; it's the smaller diameter cylinder that you see when you unscrew the damper knob/piston
The Owners Manual recommends using the same oil and viscosity that you put in the TR6's engine.
Click to expand...

Well, I think we found the problem. Recently we had installed an electric fuel pump. Today, removed the mechanical pump, installed the backing plate and removed the old fuel lines. Just as a precaution, started the engine - and would not start. Short story - we had bounced against various wires and the wire from the alternator to the coil had come loose. Once that wire was securely reattached, the sputtering problem disappeared. Our guess is that the wire had been loose all along so the coil was not getting a steady current. Longer trip later today to test (90 degrees in the bright sun is just too hot). Hopefully, this problem is solved.

Thank you for your help.
 
There you go !....
poolboy said:
There's an adage:
"90% of carb problems are ignition problems"....with that in mind I think I'd check the ignition timing at idle if only by ear...you can't be that far off.
Click to expand...
 
Question does temp make a differents ? Your CD 2 carbs have a diaphragm on the top under the four screws remove top check for a hole and or lost it's flexibility it should be almost like a condom. If you find one bad change both. I carry an extra one as I have lost a few. When you remove to check note they have a key notch that has to go back in it's slot; Question does pulling the choke out help? You should not be running at full rich you have covered up the problem Madflyer
 
Recently replaced both diaphragms (problem existed before the change). And, having the choke out does eliminate the problem. Maybe I should be asking the question of why do I need to have the carbs set to full rich? Leaning out the mixture by turning the metering needle by turning counter clockwise makes the problem worse. Fuel shouldn't be a problem, new fuel pump running a 3 psi. What else could cause a lean condition?
 
Could be a couple of things, but the last set of carbs I had in the shop with a similar complaint had debris clogging the very bottom of the jet...About the only fuel available was that supplied thru the choke.
 
Cleaned the rear carb within the last month and replaced the metering valve. No apparent debris in the bottom. Also replaced the float. Didn't touch the front carb as the rear was so clean. Always a chance that the front carb could be a problem.
 
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