Mark Maras

@jalexquijano Keep an eye on the post dates. Some of the ones you're responding to are inactive now. If you want to flag someone you need the @ symbol before the person's name. Click on the person you want to flag from the pop up list and it's done. I think you're right. It's time for a new set of plugs. This may sound a bit random but humor me. Have you ever tried to start the engine without the choke when the engine is cold? When you put the new plugs in, try starting it with no choke. If it doesn't start in the normal length of time, give it 1/4 choke and try again. No Start? Go to 1/2 choke, etc. I want you to cold start the engine with the least amount of fuel (choke) as possible. When it does start, baby the throttle but keep it running at a busy idle. You may need to blip the throttle now and then when the idle starts to drop. Warm it up enough to drive it. Hit the road and let us know how it acted. The more detail the better, starting with how much choke was needed to start it.

@jalexquijano 240,260,280 and I are meeting up tomorrow. I want to discuss this with him and see if the two of us can come with a consensus of opinion.

I'd start the process by pouring hot (not boiling) water on the area in question with the hopes that whatever is holding the glass will soften. At that point a little careful poking and prying may reveal the chink in it's armor. It may be a good idea to bring the glass up to temp in a couple of stages. Thermal shock does nasty things to glass.

There may be a commercial product. In my original notes I have a reference to Thor Tire Prep #12. As I recall, this product has wintergreen oil in it. I haven't done any research on the product.

I'm going to give this a try. The theory of the solvent, as I understand it is, the solvent was supposed to soften the rubber (which it does, sometimes overly so) and the w. oil is supposed to keep the rubber from drying out again.

Interesting I've tried a mixture of wintergreen oil and Xylene at room temperature for varying lengths of time. My results varied with the condition of the rubber but none of them were what I would have called fabulous. Mine were more in the reusable category. Yours are fabulous. What was the other oil that you used and which oil was the 4 oz.? BTW, good job on the videos.

What were you playing, Robin Trower?

I'm thinking of a combination of the two. They could have put that old mechanical sound on the beginning of CDs. Perhaps now one could add it to streamed music.

We'll get back to the fuel level, I just want to know how it runs now to use as a baseline for further adjustments.

@jalexquijano If it were me, I'd fire that thing up and see how it runs and drives cold and warm before altering anything else. I've learned that one step at a time and see what effect that one step had is the best way to learn diagnostics. Might take a little longer but I've experienced the, "I'm glad I was able to fix it. Now I just wish I knew what fixed it" too many times.

@siteunseen At least one of the questions has been settled in the churning cauldron of symptoms and trivial facts that I call my brain. I was almost positive that it had to be too lean when it was cold, but then that creeping doubt set in. @jalexquijano Good job finding that loose clamp. We could have beat our heads on this cold sputtering problem for a long time and not gotten anything except a headache.

@jalexquijano OK. If the engine is cold, fire that baby up and see how it runs now. Take it for a ride and report back. I'm on the edge of my seat. @siteunseen Tick Tock, Tick Tock. As the official timekeeper, how much time do I have left?

That doesn't help. I don't know what your reference points are. let me put it another way. However you can do it, the measurement that would help us, is the distance from the fuel surface to the top of the tube that the nozzle slides in. The brass tube surrounds the nozzle. BTW if you turn the mixture screws CCW, (Jalex's term for leaner), to zero turns, the tops of the nozzles will be even with the top of the brass tube. I would think it would be easier to get a measurement with the choke lever pulled all the way back which pulls the nozzles all the way down. If you can come up with that measurement, we can all get back to the unsettled, at least in my mind, question of the proper float height , and as C. O. brought up, how critical is the float level in SU's? We can also eliminate one of the cold sputtering causes.

Even if the toothpick falls into the hole, it will float. There's no need to reset the mixture screws back to 2 1/2 as long as we know how many turns down they are during the measurement.

I hope that works, that would be great. If not, you could try sticking a toothpick down the hole until you hit the fuel surface and then mark the toothpick at the top of the nozzle or the top of the brass sleeve that holds the nozzle. Measurements don't have to be in the thousandths, Mm's would be fine.

@jalexquijano Good pics. I think I see a pinpoint of light reflection in the nozzle holes. I assume that pin point of light is the surface of the fuel. Can you confirm that and that both levels are approximately the same? Also, is it possible for you to determine the distance from the top of the brass ring that holds the nozzle to the current fuel level? Or, how far below the nozzle holes is the fuel? Either approximation will work.

No need to crank it up. Pull the tops and pistons being careful not to damage them. Next, with the choke off, view the fuel level in the nozzle holes. if you can't see the fuel level in the holes, that's OK for now. Next, pull the choke lever all the way back. Next, look at the tops of the nozzles again. The nozzles will be down from the previous, no choke position. You should be able to see the fuel levels now. Verify the fuel levels are similar in both carbs.

We want to be sure the fuel level is BELOW the top of the nozzles. No matter where the mixture screws are set. No fuel above the nozzle tops is the goal. The nozzle top is the part with the little hole in it. Pull the domes, pistons and take a look at that little hole in the center of the nozzle. Now pull the choke on and take another look. You'll see that the nozzle has been pulled down. If you couldn't see the fuel level in the little hole before pulling on the choke, you should be able to see it now. While the choke is on (nozzles pulled down), it's a good time to compare the fuel level in both carbs to see if they're the same.

I want to verify that the fuel in NOT puddling on top of the nozzles at 3.7 turns down. You'll also be able to verify that the float level in both carbs is the same. I still can't figure out if the sputtering when it's cold is caused by a lean or a rich mixture. At first I thought it was getting too much choke but if the the engine runs worse when you ease off the choke a little bit, the mixture is too lean.

No need to readjust yet. I'd just like to know where the fuel level is to use as a reference point and to be sure the fuel level isn't too high and puddling on top of the nozzles. Also, I'd still like to know if easing the choke off a little when the engine is sputtering and cold makes the engine run better or worse?

@jalexquijano When it's cold, sputtering and the choke is all the way on, what happens when you ease the choke off a little bit. I'd expect that the sputtering would go away or get better and the engine would run a little better if the mixture is rich-normal. If the engine wants to die, especially under a load, the mixture is too lean and we need to take a look at your choke cable adjustments. The cables may not be pulling the nozzles all the way down, which is full choke. At some point in time I still want you to pull the domes and pistons so we can verify the fuel height in the nozzles.

Drive it. You'll get to experience wiper lift.

That's going to be the quietest Z on the face of the earth.

@jalexquijano Ditto what Cliff said. Swap #4 plug with any other plug and see if #4 cylinder fouls with a different plug. BTW, I'd like to see a little Never-Seize thread lube on those plug threads.

Could be #6 was tested first. I retest the first cylinder when I'm done and usually find the C. R. has gone up a bit.