- How long do you guys give a sticky needle valve to fix itself, once you have tried all the tricks? Do I just hang in there with faith it will fix itself?

- Is there a workaround for sticky valves? Saw something called a Grose Jet, but seems like it is no longer made?

Have a chronic flooding issue. Car is otherwise running great so very frustrating. Was driving around this morning like the opening sequence of the Italian Job (original version) when splutter-bang car dies on me.... Again. This has happened a half dozen times. Does seem to be sticky needles as can stop the flooding with a sharp tap on the bolt that secures the hard fuel line to the top of the carb. Happens every drive, usually a ten to fifteen minutes in, so gotta fix it as can leave me in a dangerous situation when the engine stalls in fast moving traffic. I carry tools and spare plugs so can get it running again in a few minutes with the usual pulling plugs and de-flooding routine.. but man I just want it to not happen. If its any clue it does not seem to happen at a constant highway cruising speed, but seems triggered by engine braking ie a winding downhill road or a freeway exit.

Over the last few weeks have tried both the original valves/seats, and new valves/seats from Atkins. Burnished the corners of the needles in both cases by lightly rubbing on a chromed wrench with some light oil, a minute per corner. Tried light oil on the springs inside the needle. Set float height to correct spec, and when the problem continued tried setting the floats 2mm lower (installed orientation) so they press harder on the needles, still flooding so reset them back to spec. I ran the original needles for around 200 miles, approx 20 starts before giving up when problem persisted. New needles have maybe 20 miles on them, but just stuck twice on a short drive, so grrrrrr.

Can I trust this will break in and go away, or is there something more active I should be doing?

Is there a workaround?

Anyone invent a device that can give the top of the carb a sharp rap as you are driving along? (I am only half joking about that one).

12A 1981, all original. Recent engine and carb rebuild. California car so cant be swapping much out as need to pass smog.

 

And a follow up. Just in case it’s the vent solenoid causing the flooding... is the there a way to jam the vent in the open position? (Assuming the vent should be powered and open when engine is running). Just want to be sure I am not barking up the wrong tree.

 

Yes the bowl vent should be powered and open when the engine is running. If not you will have flooding problems. As I remember, kind of random flooding. Is your bowl vent powered at the moment?

In the process of stripping carbs for racing, those vents are typically eliminated. There might be instructions in the archived files. If not, it is not to difficult to gut them. They are basically there to vent the bowls to the carbon filter when the car is not running. I am not sure how they would be able to tell if the vent is working or not if it is gutted, but still has a wire connected. But then as long as it is connected and working that should not cause any problems.

Carl

 

Ended up taking it apart and testing it. All working. A nice solid ‘clunk’ when I put power through it and I can see the valve move.

And.... not to count any chickens... I may have fixed the sticky valve problem. Threw EVERYTHING at it. Reused existing seats. New needles. Spoon buffed the corners of the needles. Polished the insides of the seats with Brasso and QTips in a drill. Polished the spring tabs on the floats. Reassembled the floats and needles and spent a solid ten minutes manually jiggling the floats up and down hoping the motion would buff out any remaining rough spots. Just went for a 40 minute drive with a couple of restarts and no flooding. Going for a more challenging drive tomorrow when I have a passenger who can push should I stall in traffic! Wish me luck.

 

Do you have an aftermarket fuel pump? Sounds like you’ve exhausted all your needle valves/seats and floats options. They say that these carbs need a low fuel pressure otherwise it will flood. If you have an aftermarket pump try getting a fuel pressure regulator that can go to the 3 psi range.

 

Chirmstream. Interesting idea. I just need a way forward should the car start flooding again. Pretty sure fuel system is stock all the way from tank to carb, but if there was hope in adding something with an adjustable pressure it would give me reason to keep trying. So far the latest needle/seat polishing seems to be holding but have yet to really push my luck with engine braking which seems to trigger the problem.

 

Quick follow up. Took the car on a more challenging drive with freeway, stop/start and hills up and down. Ran really well and even got a Nice Car from the guy in the auto parts store where I stopped for two stroke. Fingers crossed but seem to have fixed the sticky needles. If I was to guess what finally did it.... polishing the insides of the seats with Q tip and Brasso in a drill. Suspension and steering next.

 

Nice work!

 

Ive tried everything trying to make the new crappy needle valves work on a few different cars. Best thing to do is find an old unmolested parts Nikki. Use the floats and the needles out of it. Most of the time u don't need to adjust the floats.when using the old ones. When u adjust your floats for the new needle and seat. The floats are a pain in the *** to get right when u try and go back to the old needles. I've always used grose jets. So when I rebuilt a friend's carb with no goose jets to use I discovered this problem. I got so good at taking the lid off the carb I could do it with my eyes closed. For weeks I was playing with several different sets of new needle valves. Nothing worked. Friend gave me a old Nikki for parts. Problem solved. There is no breaking in the new needle and seats. They belong in the trash. Ive yet to find a old worn out needle that I couldn't reuse.

 

Run some seafoam every few months , it really does help break up all that gunk and varnish.
Also + 1 on the oem jets and seats, the new ones can be used but you have to polish them well including the holes , you need to do that with special tools like a dremel wand , the wand press a vice and steady hand . Glad you fixed it.