Nikki carbs for 31 and 33 series Briggs??

[Arkie]

Has anyone else noticed floats on Nikki single throat carbs that does not set level due to a shorter needle as compared to the ones that set level having a slightly longer needle?

I have been going through some Nikki carbs (single throat) that are used on the 31 and 33 series Briggs vertical engines. Guy gave me a pile of Nikki's because he just installs new. (smart fellow)

The carbs with the shorter needle which causes a higher fuel bowl level and flooding in the carb throat and engine appear to be the real deal Nikki's but I'm not sure.

When testing on a 33 series engine I'm finding some that flood the engine and when I pull the float bowl on the ones that flood I noticed that the float does not set level when the carb is inverted causing a high fuel bowl level.

On the Nikki's that float sets level I've found that the needle is slightly longer and the correct needle to correct the high float levels is in this kit from Amazon. I just happened to have one of these kits with the longer needle so as to check for a level float level when the Nikki carbs are inverted.
796184

https://www.amazon.com/dp/B092D3CYYC?ps ... ct_details

[KE4AVB]

I haven't had problems with fuel over flow except when the transfer tube gasket set is bad. Plus depends if the needle valve is spring loaded (soft seal) version or a solid needle. Soft seal needles do have the float that can drop below level when inverted.

[Arkie]

All these are the soft tipped needles and the body length of the needles is different in these Nikki's.
The shorter needles allow the float to almost touch the carb body when the the carb is inverted.
Installing the longer soft tipped needles ONLY into these carbs makes the float set level.

I'll get back in a few days with a follow up report after I've test run some engines with the float setting level using the longer needles.

I've also seen the bad transfer tube seals and o rings causing flooding that you mentioned.

[KE4AVB]

It would be interesting to find out if these are OEM carbs or not. Plus if they were service with an aftermarket kit. I see a lot junk out there. And several so called shop in my area are installing clones lately. I had one last year that I had resize the idle jet because the engine was surging so bad that it was doing even under load.

[Arkie]

I found from engine testing 0f the flooding Nikki carbs that the shorter needles and the float level was not critical and NOT THE CAUSE OF THE ENGINE flooding.

The flooding was due to the molded bowl gasket #7 at this link.
https://outdoorpowerinfo.com/repairs/br ... i_carb.asp

This bowl gasket when bad (detoriated) will allow the needle seat gas fuel flow to bypass above the needle and seat and flood the internals of the carb. (fuel will bypass above the plastic piece even though the needle and seat is good)

NEXT QUESTIONS ABOUT NIKKI' carbs?b's

At this link https://www.ebay.com/itm/172997566154
When is the half moon intake gasket used?
I've never seen one in use on a engine. Appears it will give the engine slightly less air or part choke so as to make the engine run richer. (MAYBE reduce the leaner engine hunting issue of some Nikki carb's???)

I also found that the OLD No Longer Available Walbro LMT carbs are more user friendly when used on the single cylinder Briggs engines as compared to the Nikki carb. The Walbro LMT will usually directly replace the Nikki' carbs when used on a Briggs single cylinder OHV engine.

Very good link for reference when working on small engine carbs: (to also view the Nikki, Walbro LMT plus others

https://outdoorpowerinfo.com/repairs/

[KE4AVB]

Long time ago Brian show me how even a nick in these fuel transfer tube gaskets can cause leaks. And I even received several new Briggs Nikki gaskets that had manufacturing defects. Luckily I got them replaced as I caught the problem quickly when I received them. Most of the fuel leaks are usually cause the fuel tube o-ring (be part of the transfer gasket or separate). Yes there two versions of this gasket.

At this link https://www.ebay.com/itm/172997566154
When is the half moon intake gasket used?

The Metal D gasket setup is called a restrictor plate. It limits the engine's hp just like it does on those NASCAR engines. When reworking carburetors if remove the intake I usually just leave them on replacing the seal. I usually find them used on the 15.5-17.5 hp 310000 series engines.

But I do see restrictor plate on Nikki twin barrel carburetors especially on JD ZTR engines. And they even use swirl plates on those engines to mix the fuel and air better.

As if the Nikki is hard to fix I found once you understand the carburetor it is just as easy as the Walbro carburetor. I even had to resize a slow speed jet (fast idle jet) in one after market Nikki last year because the carburetor was so lean.

[hanz63]

Good info in this thread. BUT if I have to replace, I put on a Ruixing carb. More Walbro LMTs would flood. The Nikkis surge. It's frustrating sometimes. Had a year or so old CH400 that the inlet pipe was corroded shut. They don't seem to be making them any better folks!

[Arkie]

Good info in this thread. BUT if I have to replace, I put on a Ruixing carb. More Walbro LMTs would flood. The Nikkis surge. It's frustrating sometimes. Had a year or so old CH400 that the inlet pipe was corroded shut. They don't seem to be making them any better folks!

I've not run across them Ruxing carbs yet. Briefly seen them listed but did not review. Appeared to be China stuff to me. thanks for the tip.
I'll try to review such.
Most generally I can make a old crusty Walbro LMT carb run really smooth and usually only require a cheap bowl gasket. (and the idle jet adjusts like it should whereas some Nikki's the idle jet is just lazy adjusting even though the carb is smooth.

What is going on with the Nikki's that I'm seeing is China is thrown in the mix and kits for the Nikki carb's may not even fit the carb you are working and some of the clones do not operate correctly when new from the CHINA factory but I've taken parts out of a NEW erratic clone Nikki and installed into a Real Nikki and got it to run ok. Playing with them Nikki's for me has been just rolling the dice and keep fingers crossed when starting the engine for a test run. (and just because the Nikki'a look same on the outside the internals MAY NOT be interchangeable or parts may not fit carb to carb.

I recently seen one of the Nikki's single cylinder engine carbs that did not have any adjustment needles at all and I would not have give a nickel for the carb when i installed for a test run and it worked great. A very unusual pleasant Nikki surprise for a change.

AND speaking of the bowls rusting, that is just a normal thing for clones even when using NON-ethanol gas. I've seen them clone fuel bowls rust really severe internally with-in one years time. (and you cannot buy just a bowl and their are several differnt sizes and configurations of bowls for the Nikki's.

Electric machines won't have carbs!!!!!!!!!!!!!

[Arkie]

Good info in this thread. BUT if I have to replace, I put on a Ruixing carb. More Walbro LMTs would flood. The Nikkis surge. It's frustrating sometimes. Had a year or so old CH400 that the inlet pipe was corroded shut. They don't seem to be making them any better folks!

Speaking of the Ruixing carbs: (couple questions below)
Hanz or anyone: Have you tried any of the $20 or less clone Ruixing carbs or do you just replace with the OEM Ruixing carb or kit the OEM Ruixing.?

I've been using this Briggs single cyc OHV 33877 1371B1 as a carb test engine, testing a pile of Nikki's and 4 Walbro's and noticed that the Ruixing carb Briggs # 594601 was also used along with a Nikki on this engine.

I found the Ruixing Briggs 594601 available as a clone for less than $20 but I did not find a cheapo kit for re-building this Ruixing. The only kits I see is a 594886 $39 plus kit for the 594601 Ruixing.

If given the choice as a replacement clone carb would you go with a China clone Ruixing or a Clone Nikki????
ONE reason ask about the maybe better of the two China evils is sometimes I get clone carbs for 2 cycle engines and small 4 cycle engines from Amazon prime and if they are no good I can get a refund and free return shipping.

[hanz63]

I have only used the Ruixings out of the Briggs box. Are there actual Ruixings sold on Amazon or something? It may be my shortcoming, but I've had several of those Nikkis that would hunt badly. New intake seals and gaskets. Thinking a low speed circuit issue, I'd clean "up" where I could and they would let me down. The Ruixings have that removable pilot jet so maybe... We'll see after they get a few more years. On new units I get dead solenoids on these, but no runability. Of course, you need to but a couple bowl seals in stock for them. 594861 if you haven't already. Any leads on aftermarket actual Ruixings could be helpful. PD likes them $$.
Corroded Chinese carbs are nothing new to me either. I should just look at the Kohler carb and see whose handy work that was. Some corrosion around the shut off valve on that one in the aluminum body. A tiny bit of rust on the bowl if I recall. The steel elbow that lets fuel into the valve assembly wouldn't clean or even open a smidge. I thought about dropping the elbow part in some sulfamic acid, but I knew it would just turn into rust problem again. His fuel had a high water content, but it didn't really break. Just a few drops of water. Fortunately the plating in the tank looks top notch. He'll need it keeping the machine in a breezeway.