Nikki Richer Solenoid Fuction/Delete
 

tl;dr - Can I unclip the power to the richer solenoid on my nikki carb? Or do I need to run power to it?

I'd like to know more about how it works and I know there are a few Nikki experts on here. I recently removed my rats nest, which also removes the vacuum switch which operates the richer solenoid on the carb. See richer solenoid below:
https://cimg7.ibsrv.net/gimg/www.rx7...95ca452c31.jpg

There is conflicting information on the forums and on the internet of its function. Some sources say its open at idle and closed during deceleration(1985 carb manual), others say its closed at idle and opens during deceleration(1980 carb training manual). Ideally id either like to remove/plug it(making the circuit permanently open) or just unplug it(leaving the circuit permanent closed). If i have to, I can hook the vacuum switch back up to make it factory functional.

It seems like Sterling/Yaw carbs had the hole plugged permanently, which would leave this richer circuit open. On most "Nikki stripping" tutorials, it says to just unplug this solenoid, which would make the richer circuit permanently closed.

Any input?

The way I've deleted this thing permanently was to take some 3/16" aluminum rod, cut about 1/2" or so, smooth one end, drill a tight 3/16" hole so the rod has to be tapped into it with a hammer (use a digital caliper to find a bit that is just a little bit smaller) and drill a guide hole slightly larger just at the opening of the hole for easier insertion.

This hole is located under the main body and communicates with the little brass jet the factory pressed into the baseplate on 84-85 carbs. Some SA carbs also had a richer solenoid and can be deleted in the same way. See if you can locate this hole and find out how deep it goes as all of this is from memory but I plan on deleting four more of these things.

You can leave the baseplate alone.

I like to use red loctite on the rod piece so it can never be removed easily. This mod worked great on every carb I've done it to. No leaks at all. I've also blocked the large threaded hole with quick steel but it's up to you. I don't think I'll be doing this last step on the carbs unless there is a turbo oil feed line in the way.

Jeff, thanks for the response, it was definitely helpful. So in short, plug this idle richer fuel circuit in the main body?

If I wanted it to be less permanent for the time being, it sounds like unplugging the solenoid would keep the plunger engaged and block the idle richer circuit, achieving the same result as above?

Yes, main body only.

To do the temp way you describe would get an ok result but some fuel does still seep past the needle and gets down into the baseplate, then it affects the idle richness. You can do a temp blockoff by using a gasket which has not been punched here. The paper does get wet with fuel and can tend to break down over time, but it could take a year or more.

I successfully deleted the four I mentioned today with 3/16" aluminum rod. Wasn't that hard to do but a little intimidating. But then all Nikki mods tend to be this way.

Excellent, thank you for the response. I followed your instructions and drove a brass plug into the main body idle richer circuit. Much cleaner install for sure. Thanks again for the advice, hopefully this can help someone else out in the future.

Yay!

BTW, if the richer solenoid/spring/plunger you removed is in really good shape, I'd be interested in taking it off your hands as I'd like to have a good spare in reserve - - I'm still running smog-legal & my current richer solenoid is original to the car.

Divin, you should mention you need the SA style.

:blush: Didn't realize they changed the richer on the FB carb?

They seem to have. I modded a 1980 Nikki the other day and noticed it had the longer solenoid body like a 79 and only one wire. FBs are two wire. Is yours one or two wire?

Being a Cali carb, mine has two solenoids on that side of the carb; one the long hex-shaped single-wire for the richer as part#90 in the diagram above, and the other shorter, round, two-wire variety, and situated on the throttle plate which runs the Vacuum Power Valve circuit, part #127.

Far as I can tell from the carb manual, 79-80 & 83-85 man-trans carbs used the same (thin hex-shaped one-wire) richer on the same boss on the main body, and 82-83 didn't have one.