Solex 34 PAITA/PAJTA tuning and timing issues

[Wolfbane323]

Hello all, as of recently i was finally able to drive my 1960 220Sb to its new home with the help of CTH350 i was able to get a new head and make her come back to life... at least for a few moments since she didnt and doesnt want to idle correctly, i made sure the timing was ok and dwell was ok between 37-41 degrees per spec of my book and we took it out but she kept wanting to die at idle and it was a gigantic mess, to a point i thought we were almost out of gas but it was ok, then we got going and we were cruising ok until she didnt want to give any power but THEN she would idle and right now its a mess, i just have no idea where to start on tuning this car since im back to square one, on the bright side idont have to travel some 10 miles to work on it anymore but at the same time i go to sleep frustrated since i didnt really get it going good yet which is kind of infuriating since the whole time i had this car its had its ups n downs (mostly downs) but its still there i guess. Anyway i need a few things, where to start, How to start and essentially the steps to tune it right

[Wolfbane323]

Okay so here is where im at with my issues, as of recent I have managed to get the timing down on the spot and the vacuum advanced working again and I know all that is correct to the T in the book. the valve timing and adjustment is in spec, the chain is nice and new and everything mechanically is great, but now I have the issue of the carburetors. these stupid things get on my nerves so much because here is the issue im having now. the carbs (when theyre warmed up of course) the car idles fine, maybe on the slow side but im kinda not sure what im doing. I got an air flow meter and I got both with the linkage disconnected flowing 9.5 kgh (kilograms of air an hour I assume) and when I connect the linkage and blip the throttle a little the airflow remains the same with both at 9.5. now the idle mixture I disconnected both carbs from linkage again and turned the idle mixture screw in till it started to slow and start dying on first three, then I backed it off till the engine started to accelerate and kinda found the midpoint of the first carb, repeated step for the second carb and I guess theyre tuned? I have very little experience doing this firsthand.. anyway but heres the main issue, when I push the throttle and kind hold it open for a little while and then just let it go and try to idle again, it bogs down itself and dies, why is this? is the injection amount wrong? is the idle mixture still wrong? in other words I have no idea, also I noticed when I actuate the throttle linkage the accelerator pump lags and kinda is slow to respond, is there anyway I could fix that so it reacts better and the engine isn't hunting when im trying to accelerate or rev it up to go? I sprayed some wd-40 on the points where it piviots and where it slides on the rod for the actuator for the pump and it helped but it still kinda lags unlinke the second carb where it opened pretty easily. so issue 1 after acceleration to idle car dies, issue 2 fuel injection pump for 1st carb is slow to respond. any help would be appreciated

[cth350]

air flow and idle screw positions must be consistent so the amount of fuel for the air flowing is consistent. The actual numbers from the air meter are all relative. The presumption is that it's off a little on each carb when you put in place, so it should be uniformly off for each one. (It's also that Heisenberg thing about taking the measurement disturbing the system under test).

If you move the throttle by hand and let go, it should immediately return to idle position. The carb might take a moment to react, but the physical linkage with its springs and pivots should respond as quickly as you can imagine.

Ah, these are the older carbs, there is a little tube that is supposed to be filled with oil to act as a damper on how the throttle moves, it has a counter-weight too. That mechanism in that tube might be binding and it needs to be reloaded with oil. It's a 10W oil, transmission fluid or Marvel Mystery Oil both work fine for it.

Also WD40 isn't a lubricant. Use a light machine oil or white grease instead.

-CTH

[Wolfbane323]

Not sure what the heisenburg thing is to be honest, but i understand somewhat about if i adjust the idle speed i have to counter with the idle mixture since im sending in more air i need to send in more fuel too no?

When i blip the throttle course it reacts and returns to idle but then it bogs down alot and if i had the accelerator open for longer than 3 seconds and then let it return to idle it bogs down till it stalls. Plus when i slowly open it i notice the accelerator pump actuates fully at WOT on the second pump but the first one slowly lags behind the second carb which is why i wanted to use wd- 40 to try to make it move a little better but alright, ill try to see if i could find some white grease to see if it helps some more.

Im not sure how to refill it, ive heard of it but i dont have an applicable gun or equivallant to shoot some oil into it.. also how would it work with the carbs? Why do the carbs need a damper? Or should i say whats the damper do for softening the throttle? Sorry if im not wording this right but i seen it and i kind of lifted it but im not sure what it does in terms of dampening or im not sure how it works.

[barry12345]

You have wd40. Spray it around the base area of the carbs. If their are air leaks the idle will pick up.


Sometimes it helps to mentally break down the way carbs work. I would want to pay strict attention to the idle circuits at this time. Have you internally cleaned the carbs?


Post if their are any air leaks discovered. If there are not I will suggest to you a way to cheaply clean the carbs internally.


What happens to a lot of them is as the gas dries out in sitting a varnish or dried gas residue is left behind. I usually remove the idle mix screws and look for decent flow out of the ports. The dried gas residue seems to like to accumulate in those idle circuit passages. New gas does not dissolve it. Or if it even does it would take a very long time if ever.


My way of cleaning is both effective and cheap without removing the carbs from the engine. All too often these carbs become essentially problematic from sitting around too much with the gas evaporating from them and leaving behind a nasty build up. Zenith carbs especially may have a worse reputation than they deserve because of this.


Even when I think a Mercedes m130 engine is running pretty well. After I clean the carbs they always seem to run still better. So when I have idle problems I first check for air leaks. Then clean the carbs. Just not the conventional way.


I separate the fuel line under the drivers floorboard at the firewall area. Plug the line back to the tank. Run the engine until it is out of gas.


Put the front fuel line in a quart of laquer thinner. Turn the engine over to fill the float bowls with the thinner. Remove the idle mix screws. Watch the open idle passages for improvement. When thinner is flowing out of them nicely. Screw the idle mix adjusters back in .Turn each one out about one and a half turns.


Wait for another ten minutes. Then hook the fuel line back up and start the engine. It will run fine on the laquer thinner remaining in the carb and whatever it has dissolved. Till the gas gets back in. I use this on small carbs on many other gas powered items like generators, lawnmowers etc.


Try to look at your carb problem from this perspective. With the plate in the throat almost totally closed. The intake vacuum of the engine. Pulls the fuel in from those passages under them to idle on. As the plate opens the vacuum suction effect is being reduced. That gradually disables the idle circuit. So if there are no air leaks adequate engine suction is present. If the passages in the carb are clear the suction can pull gas from them. Keep it simple initially. Do not get distracted by anything that has nothing to do with the idle circuits.


I guarantee nothing other than it works for me and my son in laws every time. When an engine was running well a year or so ago and will not run right a year or so later. After sitting with gas in the carb unused in that time frame. Actually to store a carb for longer term idle periods they are supposed to be filled with light oil. Seldom if ever done.

I developed this a long time ago when faced with taking apart a couple of Zenith carbs. Soaking them in carb cleaner and kitting them .I thought about the time and cost plus disturbing the gaskets under the carbs if they were not leaking air. It worked and worked well. My first reaction was the amount of time and money I probably had wasted in the past. When this was so easy, cheap and logical to do. A brother in law now uses it frequently as well but substitutes the solvent he uses.

[dobrodan]

You don't mention if the fuel enrichment valves - sometimes mistakenly called chokes - are functioning properly. Pulling the knob out, the first detent is a fast idle and all the way out is full enrichment for cold starting. The three position valves operated by the cable/linkage can be positioned incorrectly if the lever is removed. If one or both is off by 180 degrees the engine will never run right.

[barry12345]

Different carbs than the zeniths. Still to a point most carbs basically function the same. You want them clean internally before anything.


Based on the chance that they probably were fine the last time they were used. Or the car would not have been driveable.


Trying to compensate for dried up gas residue can sometimes work. In many cases it just will not. I just no longer waste the time.


If the engine is not running properly with carb issues. After sitting a long time. I clean them first. It does seem to work well often enough I can get them back on line or they already are after the cleaning. For example I have the nicest running m130 engine I pulled and put into storage years ago.


I do not expect the carbs to be right when I run it again if ever. I should have put the light oil in them but did not. Of course this one may fool me. I have three m130 engines and perhaps 10 zenith carbs.

[Wolfbane323]

sorry everyone, my ipad croaked at the beginning of the week, it was my main connection to the internet since im rarely on pc and I hate my phone for internet use. my ipad was like a mobile comp and its been down since Monday night. anyway well I managed to fix the idle down issue, they were a little lean and after I enriched the mixture slightly I reved it up and tested it and it never died down on me again, now what was happening is when I accelerated the engine bogged and sounded like it had no power but now what I noticed was the accelerator pump spring was lagging ALOT on the first carb so I replaced the spring with a stiffer same length spring and boom, not as much lag since I didn't replace the other one (working on it) so everything is good there, but now there is another issue arising my concern, is the water pump housing separate from the engine block? it appears to be leaking and it cant be the pump because I just replaced it, the banjo bolts below them look dry and the thermostat housing under the gasket is also dry, also I fixed an oil leak from the chain tensioner because it was also leaking oil from the o ring. just wondering if the waterpump housing is separate and replaceable or if im going to need a whole new engine oooooof. anyway ill check back here if and when I get my ipad soon or get a new one