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General Tech Engine Trouble--Can't Figure it Out

"My mixed plugs are Champion and NGK."

Which Champion plugs, and which NGK plugs? Are the spark gaps set correctly?
 
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All my British carb cars, I use Champion because they clearly can be cleaned vs NGK, Dense and ofhers. I have a plug cleaner who h has cured a lot of problems for me. Bad gas,etc. Most older cars of British motors used a .025 gap.
 
I did everything you have done. Please let me know that you checked the fuel hose coming off of the pick up tube coming out of the fuel tank. My fuel line hose was pinched just enough to allow the car to start and a vacuum was created in the fuel line cutting off the flow of fuel. My vapor line going to the charcoal canister would in time vent the vacuum in the fuel line and allow start up.
Pull or move the fuel line at the fuel tank and make sure you have plenty of fuel hose so it won't pinch closed.
 
I have checked that line. I think I’m good there. The one thing under the car is a kink where two steel sections are joined by rubber fuel line. The alignment isn’t perfect, maybe a 5 degree kink, but I just can’t see that as a problem. A friend says my tank must be vented, but I believe the standard Triumph gas cap, itself, is vented with a notch in the upper sealing ring. I’m still wondering if sediment is floating around in the tank. My camera detects something looking granular near the outlet fitting, but the fitting is raised and I also doubt that would be my problem—which is intermittent cutting out, hiccups and stalling. I solved my coil arcing problem and now I’m focused on why my forward spark plugs were fouled up with carbon as if way too rich. I definitely think those plugs were failing. They were that messed up, and I’m thinking the coil was a separate, but maybe contributing, issue.
 
Did a kid put something in tank?
 
I feel your pain. I was frustrated at the constant stalling and checked and rechecked all of the items you have. I had installed an Italian made fuel pump that worked well. I had issues with domestic(chinese) pumping varying amounts of fuel. I traced the fuel line back to the tank. I had replaced the fuel cap gasket and thought maybe small bits of rubber was clogging the pick up tube. There was fuel hose coming off the pickup tube the was too short and as the fuel pump pumped it then collapsed this hose. My fuel tank is only vented by the vapor line as per design. I hope you find the issue...I would have never guessed this was my cure.
 
Question: Would four flats too rich on the jet adjusting nut be enough for the car to sputter and stall? My plugs on the forward carb, pistons one and two,were literally caked with carbon soot.

I’m not ruling out the coil, but I rather doubt the coil is the only problem, since pistons three and four were apparently burning fine and the plugs look good.

I can’t see that there’s a valve issue, because I would have to have simultaneous valve problems in both pistons one and two.

I’m actually thinking that having NGK plugs in pistons one and two, and champions in three and four was problematic.
 
Which NGK plugs, and which Champion plugs?

And what are the electrode gaps in each?

Also, if you have a slight kink in a fuel line, that's a perfect spot for crud in the fuel tank to get caught and cause fuel starvation. Do you see any crud in the fuel pump glass bowl?
 
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Try backing off 2 flats on the 1& 2 carb. If no change Install 4 new properly gapped NGK(IMHO) plugs. Put a see-through fuel filter between the tank and the pump to catch any possible crap from the tank. My .02 Karl
 
Again, you can't test a coil, because most problems occur at high voltage (like internal arcing) and you just can't test a coil at high voltage outside the car. You can do resistance tests with a multimeter, and if the coil fails those it is definitely bad. But if it passes them, you can't conclude that it is good. Only way to be sure is to replace it.

Furthermore, there is little difference between coils. The "high voltage " or "sport" coils are a con. Just get one with about 3-4 ohms primary resistance and you'll be fine.

You won't get the carbs right by randomly fiddling with the mixture adjustment. They really need to be retuned properly. But before doing that, it's important to have the timing and valves adjusted right, as they affect the mixture. And plugs are cheap, so replacing them is prudent. Plugs can go bad, too, and you can't really test them.

And, yes, be sure that the gaps are right. Too-wide gaps might have caused your earlier arcing.
 
FWIW, on ZS carbs the jet sits about 1/10 of an inch below the bridge...If you want to use that as a baseline for the SU carbs, I think I'd start at 0.12 or 0.13"
 
Hmmm. I’m now more like 1/15th below the bridge. I’ll watch and play a bit. My timing is right on, and the two carbs are balanced. The rear carb mixture s set perfect. Valve adjustments were made 7 months ago, but I suppose I can recheck. I might throw in a new coil if I don’t see improvement.
 
I know it's fuel or carb related due to the fouled plugs 1 and 2. Or something really off on the valve timing which I'll check later today. On that forward carb and fouled plugs 1 and 2, I'm seeing a leak at the fuel hose to the jet. Very slight but a leak. In addition, my two carbs have different jets. I think I'll try rebuilding these carbs. I have all that I need and a good shop for the spindle bushings. But I'm a realist. I doubt this little leak problem is causing my plugs to foul. All else with that carb--needle, housing, butterfly, seems fine.

But, as usual, I have a question. I let the car sit for ten days. When I took the lids off the float chambers, my rear carb float chamber was full of fuel. When I removed the lid on the forward carb float chamber, it was almost empty. Again, that leak from the jet line is slight. Rubbing a finger under the connection shows wet each time, but there is definitely no drip. Does fuel dry up in the forward bowl after sitting, or is this more likely a leak issue. I have new jets in my modest little shop, fyi.
 
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