• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR6 TR6 not Running Properly...Suggestions

Share this page

gbtr6

gbtr6

Jedi Trainee
Country flag
Offline
Hello, My 74 TR6 isn't running well. I have a Pertronix, Dwell gap dead nuts on 35,I also adjusted the valves, to .010 cold. I have SU HS-6's on it. It hasn't run since more than a year ago. I sispect bad gas but...I started it and it runs on the choke, but only at around 1500 rpm. After that, if I put the choke in, when it's warming up, it doesn't run, drops right off. As an experiment, i took starting fluid and sprayed a shot into each carb. into the front one, immediate reaction, rise in rpm's. Spray the rear one, nothing. This is on the choke, at @1500 rpm's. I'd think I'd get a reaction like the front carb. The throttle shaft rotates. I'm puzzled. Any thoughts???

Thanks,
Perry
 
Nice color TR6! I can see that you have good taste in Triumphs. Welcome to the Forum.

A few basic questions.

What does the fuel filter look like? Clean, cloudy, rusty?

How about the screen in the fuel pump under the top cover? After lifting that screen, is there any junk in the pump?

If they're OK and pressure is 2-3.0PSI, fule is OK.

How about the distributor rotor? Is the center loose?

OK, then how about the cap? Any marks or cracks?

Did you check for vacuum leaks?

Are the diaphragms in the carbs OK? Oil level OK?

Let's start there.........
 
Haven't checked the filter in the fuel filter, didn't know there was one.

Clear in line filter before the pump, looks clean, is new.

Distributor is OK as is rotor.

Cap is relatively new, think it's OK.

I sprayed around the carbs for leaks and didn't notice any changes.

Topped up the carbs with ATF. No diaphragms as they are SU's.

Puzzled a swhy it wouldn't pick up when spraying starting fluid into one of the carbs. I think I need to rebuid them, and clean them.

Perry
 
It might be a good idea to take the lids off the float chambers and compare the fuel levels.
 
Forgot to mention, i checked timing and at 1500 rpm, it's at 18 advance, but when I rev the engine it doesn't move much. I don't think the mechanical advance is working. And, i plugged in the vacuum line, and still no advance.

Perry
 
Plug wires are correct as it doesn't run rough, just no power and revs fall off. Have had wires messed up before.

Perry
 
Have you checked that the carbs are balanced and that the chokes are opening evenly?
If not then that would be a good place to look, if one of them isn't doing any work then you can spray ether all you want, but without a throttle plate opening it won't make much difference
 
SU's after sitting can have the jet tube and line clogged by "jellied" fuel. If you remove the dome chamber and spring/piston/needle you should see fuel to the top of the jet. If it's dry the line is somehow blocked. ~Sometimes~ a spray can of carb cleaner with a plastic "straw" blown thru the jet orifice can clear 'em. MOST times it means an R&R and a good cleaning. Are they older SU's with side-mounted float bowls or the later "emissions" ones with integral float chamber?
 
These are the older side mount bowls. I had hoped to run it a bit before rebuilding them, but it's been a long time since I've rebuilt them.I had set them with a Unisyn, I'll have to recheck. The front carb seems to be the only one working, which explains why it pukes off choke and when I try to accelerate.

Thanks,
Perry
 
Perry, it MAY even be an issue of a stuck float/needle. A couple smart taps with a screwdriver handle on the top of the rear float bowl could "fix" it temporarily. Not TOO hard, mind. Just a thump or two.
 
took the top off the fuel bowl on the rear carb and it has a lot of sediment in it. I think I'll rebuild them both and start relatively fresh. I imagine the fuel pump screen is the same. One question though, when I spray the ether in the carb, if the throttle plate is cracked open even a little, it should react, correct?

Thanks,
Perry
 
Try giving it a whif of the start fluid while holding the offending carb throttle open manually (by it's linkage) to see if it makes a difference.
If it doesn't then I would suggest that you may have some other problem, maybe ignition, perhaps mechanical (any comression?).

Before tearing into the carbs, I would try to figure out whether the offending carb is working by loosening the linkage between carbs and operating it manually by adjusting the idle speed screw on the bad one.

While on the subject of starting fluid, be careful with that stuff, it can really damage a motor if used in excess.
 
Thanks for the suggestions. Also, I don't seem to be getting any advance from my distributor with Pertronix. I need to check the vacuum advance and the springs on the mechanical advance. Any suggestions on the distributor info?

I need to check compression, but think it's OK as at a higher rpm on the choke, it sounds OK, but you never know.

I like thw idea of checking the bad carb on it's own, with the throttle disconnected from the rest of the linkage.

I think I have a few issues.

Thanks,
Perry
 
Hi Perry,

Over on the Midget side of things, everyone recommends Jeff from Advanced Distributors: see https://www.advanceddistributors.com/

No personal experience here, but everyone who has posted has been VERY impressed with his rebuilds (either stock or adding Pertronix).

HTH,
Duncan
 
The Pertronix doesn't give you the advance, that is mechanical via centrifugal force and the two springs down in the housing shown in the pictures from my web site.

If you have no advance beyond 18 degrees, your car will not run properly no matter what you do to the carbs. Your's may be all gummed up down inside there or just may be rusted. A drop of 3 in 1 oil under the rotor every season will help prevent that from happening.

Jeff can give you a curve to match your engine exactly for best performance.
 
Perry, unless you have a disrtibutor from a 70-71 car the vacuum module on your dizzy should be a vacuum retard.
If the module is on the cockpit side of the dizzy, it is definitly a retard module.
If you hook up a timing light and rev the engine you should be able to see the marks on your damper pulley move as the engine speed increases.
The pertronix is mounted to the "moving plate" same as the contact points were, so I don't think that it would be to blame for any problem with the advance, provided it was installed correctly.
You can live w/o the retard working, but not the mechanical centrifugal advance.
If you pull the vacuum line off the retard module, does the engine pick up a couple of hundred rpms?

Regarding Advanced Distributors, for me it has been the single most performace enhancement improvement that I have made. Dollar for dollar the best investment I've made engine-wise.
 
Back
Top