Mark Maras

@jalexquijano Try some different weight oils in the carbs. It would be an easy, fun experiment. (until one drops a piston or dome, VOE, be careful) I ran Marvel Mystery Oil in mine for a few years and then switched to ATF. Both worked fine with no noticeable difference in performance. Try a light weight oil as well as a heavy weight and tell us what you find. Jalex deserves the credit. He tried to solve this problem for quite a while (possibly from day one) and never threw in the towel. My small part in this was to keep Jalex FOCUSED on what WE theorized was a float level problem. I don't think any of us are totally convinced that Jalex's floats are absolutely correct but they must be close. Jalex asked a question earlier and knows these carbs well enough now ☺️ that he and I are curious what effect raising the floats 1 mm and raising the nozzles 1 turn (1 mm, 2 1/2 turns down) would have. I don't know for sure. I believe the nozzles are around 3 1/2 turns down at this time. Opinions and theories are welcome from all.

After running it through the gears at WOT and the engine won't rev to high RPMs under a load, will it rev to 6 grand in neutral? I'd let the engine idle, shut it off and pull the domes and pistons. Then pull the choke lever back and determine the fuel level in the nozzles. You should be able to see the fuel level with the nozzles pulled down. After determining the fuel levels, reassemble the carbs and run it hard until it cuts out. Shut it off immediately and pull the domes and pistons again. Pull the choke lever back to drop the nozzles and see if the fuel level is substantially lower than before. That should prove or disprove that fuel starvation is the problem.

You want it to run best under normal driving conditions which, I'm assuming, is a daily driver. It sounds to me like it's running pretty darned good. No need to go out and run the engine hard just to check the plugs. You can, however, go out and run it hard to have fun. As long as you share your fun with us. Pics are nice, videos are better. I'd like to hear it run.

They don't look too bad although #4 is still the odd one. I think I'd try swapping #4 plug wire with another wire to see if the problem moves with the wire. What is your over all impression of the way it's running? Any problems idling for long periods of time? If I was running your engine build, I would expect to have to blip the throttle now and then to clear the plugs at idle. Backfiring in the intake or exhaust? Misfiring at any RPM?

A little more info would help. Is the problem ongoing? I'd start with a complete tune-up. Did you fill your tank at the same gas station after the previous successful fuel treatment. They could have water in the bottom of their tanks. My Dad would never stop at a gas station that had a tanker sitting in the lot. He said filling the underground tanks would stir up the water sitting in the bottom of the tanks and allow it to be pumped into a vehicles tank.

@jalexquijano Is there much difference in spark plug color when you compare #s 1-3 vs 4-6? Let's try to figure out if one carb is running richer than the other.

Unless one owns a multi task CO2 extinguisher that will also chill beer.

Ditto. Float needles. Either a worn tip or crud holding the valve open.

@jalexquijano I agree with Patcon. Put some miles on it. At this point in time, don't go looking for problems. Should small problems arise, we'll deal with them at that time. Sounds to me like the carbs are finally close to optimum setting. Congratulations. You not only got it running good but you've learned a lot about SU's too. I like WIN - WIN situations. Now go drive it and tell us how much fun it is.

@jalexquijano The plugs still don't have much color but that could be caused from the gasoline in Panama. "They" tell me that the gas formula now is not the same as "the good old days". How well does the engine run when cold, warming up and at speed? Any complaints?

Thinking about this, I keep going back to a new(ish) battery that drops to 4 volts and THEN takes three days to charge. I'd have thought it would have failed the load test. I'd try another battery known to be good or jumper cables from another battery to see if the relay is still necessary. What did you mean when you said "When the car does turn over the starter is still turning over for a couple of seconds"? Do you mean the starter keeps running for a couple of seconds after the engine starts?

There was a change in the choke cable routing in the early years. I don't remember if the early routing was on the right or left side of the firewall. As I recall there was also a slight difference in the cable length too. There should be a hole there either on the left or right side.

@jalexquijano That's what we're trying to discover. Four turns down would be wrong for a stock engine. We're trying to get a little more color (tan) on the plugs. Drop the nozzles another 1/2 - 1 turn (your choice) and take another pic of the plugs after you've warmed it up and taken it for a test run.

Unsafe at any speed. A definite contender for WORST OF SHOW.

Glad to hear it's running better. Can you confirm that it was driven for a while with the choke off after it warmed up. I agree with Philip. Leave the floats alone and drop the nozzles 1 turn. More pics of the plugs after you readjust.

At least the windshield will prevent him from high siding over the handle bars. Stupid design. He'd have been better off leaving the front end alone and driving it with a single rear wheel. Wait, what am I saying. It's a terrible thing to do to a Z. Off to the pillory with him.

Thanks. Jai will have to decide. I'm not sure what the early 76 bumper looked like.

You can also use zinc rich primer instead of weld through primer. I've used it for years and had no problems welding through it. Plus, with the zinc, you get the protection from rust.

Thanks for asking. The search continues.

@Redwing Bumper pieces?

Honestly, if I was going to do it, I'd rinse the tank with lacquer thinner first, allow the lacquer thinner to totally evaporate and then use dry ice.

Dry Ice is the answer. At my previous job they removed our underground gas tanks. After pumping out residual fuel they dug around with a track hoe, pulled them to the surface and started dumping dry ice into the access holes . Probably about 20 Gals. of dry ice in each tank. The crew waited until there was CO2 vapor coming from the hole in the top of the tank. Then, to my total surprise, one of the crew stepped up to the end of the tank with an oxy-acetylene torch and started cutting up the tank into manageable pieces. As I peeked around the end of the building I was shocked that there was no explosion. Later on I talked to the crew. They said they've never had a problem using dry ice.

That was the way it was in Portland too. You could have your choice of manual or automatic transmission. That was the extent of ones options. After taking possession of a Z and driving it, the color didn't really matter as much as one thought it would. EVERYONE still wanted one regardless of the color.

Back then some of us got hooked on Z's before we even drove one. To that end, we did whatever had to be done to get one ASAP. I payed 73 sticker price for a used 71 in 73. One of the best decisions I ever made.

@Redwing Is that the bumper end you need? I believe it's a 76 but I'm not sure.