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TR6 TR6 Timing issues

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They come with the diaphram kit. The kit has a brass valve bonded to the diaphram, and at least 2 gaskets for the housing, which is a 2 piece housing. The valve/ diaphram is sandwiched between the 2 pieces of the housing.
 
Terry, I should have mentioned this. You may be able to do a simple test to see if it is the TBV in the open position that's keeping the idle from stabilizing.
If your TBV has the head of the adjustment screw, which adjust the tension of the TBV's spring, you can usually manually close a valve that is remaining open, by pressing inward on the head of the screw.
It's not going to move much, but if the TBV is open, you'll feel it move and the rpms will drop. If you want you can turn the screw in a CounterClockWise direction a few turns and the increased spring tension may hold the valve closed permanently. The only drawback is that you may experience some popping in the exhaust when you suddenly decelerate or downshift to slow down..then again maybe not.
Some carbs have a tamper proof cap over the head of the adjustment screw, hopefully yours doesn't, but the cap can be pryed off.
 
Thanks for the info. You took care of one of my issues, the vapor locking was due to the vent line having gas in it. When I blew it out there was quite abit of gas in it. I remembered the last time I filled the tank I should have stopped when it kicked off. I knew something had changed, because it had never vapor locked before. The screw that your talking about; is that the mixture trim screw located next to the bypass valve assembly?

Terry
 
No, but I'm glad you found the blocked vent line. Happened to me a time or two.
The TBV adjustment screw is much smaller and it's in the center of the TBV housing that sticks out a bit, pointing toward the front of the car.
Have a look about halfway down this page. You'll see Nelson holding the TBV between his thumb and forefinger.
The adjustment screw is brass colored and partially obscured in that picture but in the picture on the right (just above that one) you can see the screw in the housing.
As Nelson mentions in his write up, but in not so many words, some carbs had the screw covered with a tamper proof cap. If you don't see the screw, that;s why.
But you can remove the "cap" by prying and press the screw with a small round object instead of your finger tip because it doesn't project out as much as the ones on carb's w/o the "tamper proof cap".
Or you could just remove the TBV and have a look at the diaphram. If it's less than flexible, you should replace it as a matter of principle anyway.
https://buckeyetriumphs.org/technical/Carbs/CarbsII/CarbsII.htm
 
Ok, I know which screw your talking about. Mine don't have the caps on them. Tomorrow, I will try what you suggested and go from there. Thanks.

Terry
 
Ok, with the car idling, I pushed in on the head of each screw and could feel them move in just alittle bit. It had no effect on the idle speed. I repeated the process a number of times, but no luck. I installed a vacuum gauge under my dash just so I wouldn't have to keep connecting and disconnecting it every time I make an adjustment. Right now, at idle the vacuum is between 16 and 17 inches idling at about 1000 RPM's. The only problem is; when I take it out and drive it, the RPM's at idle jump up to 1300-1400 RPM's.
 
If you pushed on the screw when the engine was at 1300 + and the idle didn't drop, then the TBV must have already been closed. So they're probably not the culprit.
That's about all I can come up with except the linkage idea which might be holding the throttle disc open a little too much.
Can you tap the accelerator and have the idle come back down ?
Or can you stand outside the car and push the idle speed screws down to lower the idle when it's at 1300 or higher?
 
It acts like a linkage sticking problem, my TR3 had that issue until I removed the throttle linkage replaced the bushings straighten the rod out and put a new pin in the rod. I've checked the linkage on this one and can't find any sticking. What I have noticed is that what ever I set my idle at when the engine is cold, it increases 300-400 RPM's when it has reached operating temperature.
 
But if I uderstand right, the idle speed also fluctuates when warm, sometimes it hangs up or is it always around 1300 once you "de-choke" ?
Of course all carb adjustments should be made with a hot engine or at normal operating temperature would be a better way to put it.
That's not including the gap for the fast idle (choke), which you can set cold or anytime, really, at 5/16 inch
 
That's correct, the idle increases as the engine warms up. The problem is, when I adjust the idle after it is warmed up, I can turn the idle screws all the way up (counterclockwise) and the idle speed only goes down to about 1000 RPM's. When I let the engine cool and restart it, it won't idle at all. I have to either use the choke or use the throttle to keep it running. The only way I have found to slow the idle down is to retard the timing until the vacuum is about 13 inches. Then I have a lost power problem. I noticed after the engine is warmed up and idling at about 1300 RPM's the vacuum is between 19 and 20 inches and the power is there.
 
Well I'll tell you, that might just be a little over advanced considering the rpms.
The manifold Vacuum is usually higher at 900 than at 1300 so you'd expect the Vacuum gauge to read 17 at 900 to read lower than that at 1300. Follow me ?
So if it's reading 19 or 20 at 1300, it seems like it would be in the low 20's (overadvanced ) at 900.
See if you can get the timing to about 17..maybe 18 at 850 or 900.
 
A good low idle can be really hard to achieve with these carbs. The throttle valve shafts cannot be leaking much or the idle will be high. That's the squirt carb cleaner on 'em and see if the idle drops test. Also, that's one reason I disabled both the temp compensators and the hi-vac by-pass valves. Now I get about 800 rpm when warm with triple Z-S's.
 
I'll see what I can do. I was under the impression that when setting the timimg with a vacuum gauge you adjust the timing for the highest vacuum reading which I've done on other cars. But, I think that's assuming the carbs are working right which is questionable with these.
 
With the outside temperature at 90 degrees, it doesn't take long to get the engine up to operating temperature. Our elevation here is 2000 ft. above sea level. I got the timing at a steady 16 inches vacuum and the RPM's at about 800-850. I'm going to let it cool down and then see what the idle does when I start it. If thats ok, I'll take it out and see what kind of power I have. The way it was, I could run circles around it with my TR3, but I'm also running weber side-drafts on the 3.
 
In my experience even a well tuned TR6 has trouble keeping up with a TR3.
 
This is my first TR6. When I rebuilt the engine on the 3, I had it bored 40 over so the displacement is just about the same as a 6, but with the webers it added a big advantage of one barrel per cylinder over the 6. Maybe I'm just expecting too much from the 6. I want to use it as a daily driver this winter when there's no snow on the ground. But right now, I'm not sure if it will even run this winter. I may have to shop around for a pair of weber DVG's.
 
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