The OS CZZ is back together, but will it run?

[guggles]

Amazing, thanks for the resource! So looks like I need the orings for the nozzle assembly and then for the carb to crankcase. but some of my observations were correct about the needles themselves not having any orings on them to seal. I guess it just relies on the threads creating a fluid seal. Very interesting stuff. Thanks again.

I may rebuild mine at some point, and the connecting rod has a bit of play but nowhere near what ops had. Thats nuts. Once you add up all the prices for the parts needed to rebuild it is kind of hard to justify.

Mine would probably run ok with just new bearings, connecting rod, wristpin and teflon pucks but still then might as well get a p/s

Oh yeah and ZED32, The surging at idle problem is usually because the low speed is too lean, but heres the thing it usually only happens towards the end of the tank when the mixture is generally leaner and when the engine is at its upper temperature. Higher temperature will make the engine run more efficiently or leaner. Usually the classic tuning problem that gets blamed on air leaks, but like I said this carb only has 2 seals. so really what happens is engine wont run well when cold, leans the low speed, engine gets up to temp, wont idle down so idle gap is closed to way less than 1mm. engine can run at lower rpm but is still lean.

So basically, set the idle gap to 1mm or maybe a little less like .7 and then if the engine wont go back to idle within an instant or within a second of giving it gas, richen the ls an hour and see if that improves. Of course if the engine is at least 230f and cleared out and then immediately bogs and dies after giving throttle can try leaning an hour and see if it improves. Can also be a glow plug issue, or from lack of pinch

I always just try and shoot for the middle, lean enough on the low speed that the engine wont die when warmed up and on a full tank, but rich enough that the engine will stay at a high idle for maybe like a second at the end of a tank but then drop down into a lower idle after sitting. you can experiement and see what works best for you.

[ZED32]

Amazing, thanks for the resource! So looks like I need the orings for the nozzle assembly and then for the carb to crankcase. but some of my observations were correct about the needles themselves not having any orings on them to seal. I guess it just relies on the threads creating a fluid seal. Very interesting stuff. Thanks again.

I may rebuild mine at some point, and the connecting rod has a bit of play but nowhere near what ops had. Thats nuts. Once you add up all the prices for the parts needed to rebuild it is kind of hard to justify.

Mine would probably run ok with just new bearings, connecting rod, wristpin and teflon pucks but still then might as well get a p/s

Oh yeah and ZED32, The surging at idle problem is usually because the low speed is too lean, but heres the thing it usually only happens towards the end of the tank when the mixture is generally leaner and when the engine is at its upper temperature. Higher temperature will make the engine run more efficiently or leaner. Usually the classic tuning problem that gets blamed on air leaks, but like I said this carb only has 2 seals. so really what happens is engine wont run well when cold, leans the low speed, engine gets up to temp, wont idle down so idle gap is closed to way less than 1mm. engine can run at lower rpm but is still lean.

So basically, set the idle gap to 1mm or maybe a little less like .7 and then if the engine wont go back to idle within an instant or within a second of giving it gas, richen the ls an hour and see if that improves. Of course if the engine is at least 230f and cleared out and then immediately bogs and dies after giving throttle can try leaning an hour and see if it improves. Can also be a glow plug issue, or from lack of pinch

I always just try and shoot for the middle, lean enough on the low speed that the engine wont die when warmed up and on a full tank, but rich enough that the engine will stay at a high idle for maybe like a second at the end of a tank but then drop down into a lower idle after sitting. you can experiement and see what works best for you.

Thanks for the tips on the idle thing. Tbh I havent started it since the test run. Kinda lost interest, but also dont really want to sell it either(christ, I have issues). I need to get back to it. What would a "normal" operating temp be for the motor? Not gonna lie, I am a bit scared of getting it too hot or too lean and destroying all the work (and borderline irreplaceable parts) that I put into it. Good luck on your rebuild, especially finding a piston pin. That was a real pain to find for me.

[RC10th]

There are also a few tricks to judge where you are on the low end needle. Once the high speed is set you can work on the low speed. Note, the high speed MUST be set before you attempt to set the low speed. As guggles said the engine must be hot and keep in mind you can't properly tune on the bench, the engine has to be tuned under load. As also mentioned the engine will lean out slightly as the fuel level drops so keep that in mind.

After a high speed run or two bring the car in and while idling pinch the fuel line. It should take about 2 seconds before it starts to rev up, if it revs up almost instantly and starts to die it's too lean, if it runs on longer before increasing revs it's too rich.

You can also make a high speed pass or two then slam the throttle shut and listen to the engine idle, if the idle stays high before dropping to normal the low end is too rich, if it drops to normal first then increases it's too lean.