Mark Maras

You'll need another set but not for the test. When you Z is sitting and idling does the idle sound smooth and even or does it sound like it's missing on a cylinder or two. My guess is in the beginning it sounds ok but gets worse the longer it idles.

No, don't let it idle. You'll only end up buying new plugs. The fact that only a couple of plugs are fouled narrows the problem down to, what I believe is, poor spark plug wire connections at one end or the other. Compression is good, new ignition parts, there's not much left to blame it on. Try re-seating the spark plug wires onto the plugs and into the cap. They all should snap into place. If you have a volt-ohm meter, you could pull the cap with the wires connected (leave the wires in the loom), pull the plugs, reconnect the wires to the plugs and measure the resistance from the terminals inside the cap to the center pole of the plugs. The resistance should be nearly identical on all six. Btw, congrats on the dist removal and replacement. Success is sweet.

You know which is the "right" decision. Four days and nights is a loooooooong time on a small boat under the best conditions. Ask yourself, What could possibly go wrong? Now ask yourself what could possibly go right at ZCON. Looking forward to good conversation with you at ZCON.

@jalexquijano It seems to me that you're kind of walking up and kicking fate in the shins by letting the engine idle for long periods of time. Especially an engine with a performance cam. Performance cams do wonderful things to engines but as a rule they don't idle well and if you idle them too long the rpms start to drop and you've got to blip the throttle a few times to get the idle back to normal. In that ten minutes of idling did your rpms change at all? Perhaps you're asking too much of the engine to idle that long. And I still want to know if all the plugs were black.

NO.

I still think that the original problem with #4 was a poor wire connection at one end or the other. I think we ruled out other possibilities. That said, @jalexquijano have you explored the possibility that Previously #4 had a bad connection and now #3 and #4 have the same problem? Oh yeah, I still want to know if all the plugs were black.

I'd really like to know if all the plugs are black. If only #3 and #4 are black it narrows down the possibilities from a wide range of causes to the cap, rotor, wires and wire connections.

Check the other plugs to see if they're all black or if the problem is isolated to #3 and #4. Verify that the choke cables are adjusted properly and that the cables aren't pulling the nozzles down when the choke knob is all the way forward.

First things first. Were all the plugs black or just #3 and #4.

Flying, unfortunately.

Kathy and I are in.

You found #s three and four black. What did the others look like? Just curious if the problem is isolated to those two cylinders or all of them.

To confirm that fuel percolation is the problem, next time you shut it down when it's warm. crack the hood and let some heat out from the engine bay. Then see if it starts easier.

Since you didn't tell us "the rest of the story", I'm going to assume that when you reassembled it, the engine fired up and drove fine. Congratulations, learning is fun. Especially when it goes well.

Ztherapy sells heat shields for $100.00, no core. They list one part # but I believe there were three (somewhat) different heat shields over the years.

Do you have a heat shield under the carbs?

Sounds like the hinge pins and bushings are worn. At least, that's where I'd start. Dorman hinge pin and bushing kit # 38397 (as I recall it's for a Chrysler) will bring your hinges back into proper alignment. The doors may need adjusting after the hinge rebuild but that will be a later decision. BTW, the bushings in the Dorman kit will work to firm up a sloppy shifter. Another thought, many have reported this problem, anywhere from having to slam the doors to not latching at all. Some have gone to Kia Sportage weatherstrip. Others have used heat (your choice) to soften the rubber, closing and latching the doors and letting them set but if your hinge bushings are worn you'll just chip more paint.

A few questions. Do the doors latch and if they do how far out are the doors from the body? Do they fit worse in the front or rear of the doors?

If you get an original air cleaner housing, be sure it includes the mounting hardware.

Unanimous. Find something else to work on unless you're like me and your obsessive curiosity won't let you rest until you know what went wrong the first time around. In that case, grab a service manual, and maybe a timing light and have another go at it. You only need to remove the two lower bolts to remove the dist. If you loosen the upper one you'll screw with the ignition timing. BTW, the dist. may be original but it's been upgraded. It no longer has points or a condenser .

I'd recommend contacting ZTherapy.com and order their "Just SUs" DVD. Lot's of info and tests you can do to improve the performance of the SUs. I would fill both carbs with 20w to the level indicated on the rear carb. Fire it up and see what it needs next.

They need oil to prevent going lean during acceleration. 20w is recommended but many use ATF. There is a small indentation on the stem! Wait a minute, just looked at your pic again. Are the oil height indentations on your stems the same? In the pic I can't tell. I'm wondering if that odd cap on the front carb is from a different SU?

@mattjcr240That strange looking top on the front carb looks like the screw cap turned upside down with the "jiggly bits" and stem removed. Matt, unscrew the black knob on top of the rear carb, pull it out of the carb and compare it to what? is installed in the front carb. Front and rear should look the same. Pics please.

My early 71 had a white blade, well, more of a cream color. I replaced it with a flex fan after the clutch locked up.