RB30 Nikki Carby float level question

[dom14]

Hi Guys,
I just rebuilt the Nikki carby on my RB30.
This is a carby I bought from a wrecker who said it was not on LPG.

Carby was running fine, except the revs tend to be all over. It's around 500rpm when idling cold(or hot at times) and
then the revs jump to 1500rpm or even more at warm idling.

I decided to open it up and rebuild it with what I have. I used new gaskets(except the middle gasket which appeared to be in good nick, 1mm thick).
I took my time and cleaned the all three body parts.

I put all the bits together and refitted the carby.

Now, the revs seem to fluctuate very quickly and not running smoothly at all(the RPM dial on the dashboard is 'dancing', rather than steady).
The idling rev is 1500rpm.
The float level is as in the picture. It's slightly lower than before, I think.
It also has engine run-on for a half second or a second(engine sputtering, coughing but not full on back firing), which it didn't have with this carby before.

I tried adjusting the mixture screw, but no use so far.
Also tried idle speed screw turning anti-clockwise as much as I can, but to no use.
Ignition timing is the same as it was before the carby swap. Brand new spark plugs.
I checked the piston 1 spark plug. No carbon build up(I'll post a picture of the spark plug close-up)

I haven't tried the caby on LPG yet, because I wanna make sure it's ok with petrol first.

What I didn't do:
1) Didn't adjust the float level(it was fine before except RPM all over issue)
2) Did not disassemble the throttle body moving flaps, etc. They appeared to be fine, flaps closing nicely
3)Did not replace the needle valve or any interior parts, but cleaned them properly with carby cleaner & high pressure air.

Needle valve seat & the valve itself was different from the original carby. The end of the needle valve was a ball, not a pointy needle end(picture attached). Even though I have a pointy needle valve and a seat(used), I didn't replace it. I thought to leave it alone because it appeared to be causing no dramas)

Thanks in advance for any tips, ideas, advice.

[dom14]

Here's the video. The hissing of the carby was way too loud comparing to the way it was before.
I'm not sure why. I couldn't get it to do the engine run-on in this video. But, it's doing it now, most of the time.

It doesn't seem to react to the adjusting of the auto choke(as in the video) or even to the idle mixture screw(most of the time).

I'm not sure what I might have done/not done for the carby to come out worse than before the cleaning/rebuild.

https://www.youtube.com/watch?v=v3YNkGRo8tk&feature=youtu.be

[dom14]

I think I need to get my butt up into the gear and do some hard work on getting to know carbies more by reading some manuals and possible repair manuals, if I can find any.
Thanks for the silence guys.
It is a good lesson.

Carby is coming out tomorrow and I need to understand the 'basterds' better or toss them out for EFI.
Since everything else I use, which are smaller than cars, are using carbies, I've got no choice but getting to know them better.
What pisssssesss me off is that it's worse than before I spent countless hours cleaning it.
I reckon it's for a good reason.
I need to know them better, on my own, the hard way, I reckon.
It's a quite a steep learning curve for me to gain knowledge on a fast fading technology.
Even old school old blokes have given up on carbies, apparently.

[mudnut]

I gave my carby to a mate, a mechanic, to fit the kit the other day. I was lucky that all he wanted was $20. I would expect a 1/2 - 1 hours labour to clean the carby and fit a kit.

[dom14]

I gave my carby to a mate, a mechanic, to fit the kit the other day. I was lucky that all he wanted was $20. I would expect a 1/2 - 1 hours labour to clean the carby and fit a kit.

I can't afford to do that mate. Kind of trekking I do, I gota know how to 'fiddle' with them without fiddling. My life depends on it.
These carbies on LPG are always temperamental after they're worn out.
It would be cheaper for me to get a mechanic to fix it, but that won't help me.
Until I put an EFI dongle on the car, I gota keep the carby & learn to tweak it.
No mechanic carries a crystal ball, so I gota learn to do some stuff myself. That was the advice given to me by a pro mechanic who used to do everything for me on regular basis.(Learn to do many things by yourself or a brand new car)
My real issue here is that I haven't been able to locate a Nikki carby repair manual for this model. I only got few pages of the manual.
Manual would've helped me to locate any abnormalities and previous fiddling.

Anyway, the throttle shaft appears to be getting stuck. I need to find out why. Throttle valve flaps looked ok when I was testing them. It looks like I'm gonna have to dismantle it further and recondition the throttle shaft, etc.

I'm yet to understand the rather unusual "needle valve" with a ball end. It appears to be doing it's job fine, but startles me because I've never seen them used in auto carbies.

[mudnut]

In my humble opinion, and the reason I bought an RB30S, was for reliability and ease of fixing in the bush. Once you learn how to fix it, the carby is the go. Also now you have two, one can be kept in the vehicle as a spare. EFI may give you better power and economy, but it also has numerous components that are not repairable in the bush and that are susceptible to submersion. The ECU, the airflow sensor, the injectors, distributor, etc. Also there is extra wiring and connectors to deal with. If you are going to turbo it, the EFI is the go.

[dom14]

Yes mate, it's the same reason I'm keeping the carby for the time being. The original carby is fine, which I rebuilt myself the second time.
It's the backup carby that's been giving me more trouble since I rebuilt it. Since I paid good money for it and I need backup one, I gota fix it to be reliable.
EFI is generally more reliable, but as you explained they're not easy to replace when they do go wrong at the wrong place and time, whereas a second carby can be easily bolt on.

EFI on RB30 gives better fuel economy on petrol, but apparently not on LPG, unless I update the LPG system with a separate.LPG sequential injection as well.
From what I've heard, there's not much power increase from EFI.

Turbo is not an immediate need for me, but I'm considering EFI for the near future. Converted RB30 turbos may have reliability issues even though power increase is a great advantage.

I think, if the wallet allows you to do it, it's better to maintain two vehicles, one turbo and one non-turbo for reliability critical treks.
4WDs are like horses. They are either race horses or carriage horses. They can't be both. And that's my humble opinion. :)